European Aviation Safety Agency
Notice of Proposed Amendment 2017-06
Loss of control or loss of flight path during go-around or
other flight phases
RMT.0647
EXECUTIVE SUMMARY
The objective of this NPA is to mitigate the safety risk of loss of the normal go-around (G/A) flight path, or loss of control
of the aircraft during G/A or other flight phases executed at low-speed.
This NPA proposes to amend CS-25 to ensure that:
— the design of large aeroplanes is such that the G/A procedure with all engines operating (AEO) can be safely
conducted by the flight crew without requiring exceptional piloting skills or alertness. Risk of excessive crew
workload and risk of somatogravic illusion must be carefully evaluated, and design mitigation measures must be
put in place if those risks are too high;
— the design of large aeroplanes provides an adequate longitudinal controllability and authority during G/A and
other flight phases (focusing on low speed situations).
The proposed changes are expected to provide a fair safety benefit against an acceptable cost impact for large aeroplane
manufacturers.
Action area: Aircraft upset in flight (LOC-I)
Affected rules: CS-25 (Certification Specifications for Large Aeroplanes)
Affected stakeholders: DAHs and operators
Driver: Safety Reference: SR FRAN-2013-025; FRAN-2013-026; FRAN-2013-042
Rulemaking group: Yes Impact assessment: Full Procedure: Standard
6.7.2015 11.5.2017 2018/Q1
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 1 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
Table of contents
Table of contents
1. About this NPA ..................................................................................................................................... 3
1.1. How this NPA was developed ...................................................................................................................3
1.2. How to comment on this NPA...................................................................................................................3
1.3. The next steps ...........................................................................................................................................3
2. In summary: Why and what .................................................................................................................. 4
2.1. Why we need to change the rules — issue/rationale...............................................................................4
2.2. What we want to achieve — objectives ...................................................................................................4
2.3. How we want to achieve it — overview of the proposals ........................................................................4
2.4. What are the expected benefits and drawbacks of the proposals ...........................................................5
3. Proposed amendments and rationale in detail ...................................................................................... 6
3.1. Draft Certification Specifications (Draft EASA decision amending CS-25) ................................................6
4. Impact assessment (IA) ....................................................................................................................... 13
4.1. What is the issue .....................................................................................................................................13
4.2. How it could be achieved — options ......................................................................................................25
4.3. What are the impacts..............................................................................................................................26
4.4. Conclusion ...............................................................................................................................................33
4.5. Monitoring and evaluation .....................................................................................................................35
5. Proposed action to support implementation ....................................................................................... 36
6. References ......................................................................................................................................... 37
6.1. Affected/Related regulations ..................................................................................................................37
6.2. Affected decisions ...................................................................................................................................37
6.3. Other reference documents ...................................................................................................................37
7. Appendices ........................................................................................................................................ 38
Appendix 1: List of occurrences analysed by the RMG ......................................................................................38
Appendix 2: Synthesis of the responses to the questionnaire sent to large aeroplanes manufacturers –
RMT.0647 ...........................................................................................................................................................70
Appendix 3: Evaluation of the proportion of large aeroplanes (operated by EASA Member States operators
in commercial air transport) that are equipped with a system reducing the G/A thrust .................................75
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 2 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
1. About this NPA
1. About this NPA
1.1. How this NPA was developed
The European Aviation Safety Agency (EASA) developed this NPA in line with Regulation (EC) No 216/20081
(hereinafter referred to as the ‘Basic Regulation’) and the Rulemaking Procedure2. This rulemaking activity is
included in the EASA 5-year Rulemaking Programme under RMT.0647. The text of this NPA has been
developed by EASA based on the inputs of the Rulemaking Group RMT.0647. It is hereby submitted to all
interested parties3 for consultation.
1.2. How to comment on this NPA
Please submit your comments using the automated Comment-Response Tool (CRT) available at
4
http://hub.easa.europa.eu/crt/ .
The deadline for submission of comments is 11 August 2017.
1.3. The next steps
Following the closure of the public consultation period, EASA will review all comments received on the NPA.
Based on the comments received, EASA will develop a decision amending the certification specifications and
acceptable means of compliance for large aeroplanes (CS-25).
The comments received and the EASA responses thereto will be reflected in a comment-response document
(CRD). The CRD will be annexed to the decision.
1
Regulation (EC) No 216/2008 of the European Parliament and of the Council of 20 February 2008 on common rules in the field of civil aviation and
establishing a European Aviation Safety Agency, and repealing Council Directive 91/670/EEC, Regulation (EC) No 1592/2002 and Directive
2004/36/EC (OJ L 79, 19.3.2008, p. 1) (http://eur-lex.europa.eu/legal-content/EN/TXT/ ?qid=1467719701894&uri=CELEX:32008R0216).
2
EASA is bound to follow a structured rulemaking process as required by Article 52(1) of Regulation (EC) No 216/2008. Such a process has been
adopted by the EASA Management Board (MB) and is referred to as the ‘Rulemaking Procedure’. See MB Decision No 18-2015 of 15 December 2015
replacing Decision 01/2012 concerning the procedure to be applied by EASA for the issuing of opinions, certification specifications and guidance
material (http://www.easa.europa.eu/the-agency/management-board/decisions/easa-mb-decision-18-2015-rulemaking-procedure).
3
In accordance with Article 52 of Regulation (EC) No 216/2008 and Articles 6(3) and 7) of the Rulemaking Procedure.
4
In case of technical problems, please contact the CRT webmaster (
[email protected]).
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 3 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
2. In summary: Why and what
2. In summary: Why and what
2.1. Why we need to change the rules — issue/rationale
A number of commercial air transport large aeroplane accidents or serious incidents occurred either during/at
the end of a go-around (G/A) phase, or with the aeroplane close to the ground (but not in G/A mode) and with
the pilots attempting to climb. A loss of the normal G/A flight path or loss of control of the aircraft has been
observed in relation to inadequate awareness of the aeroplane’s state, or inadequate management by the
flight crew of the relationship between pitch attitude and thrust. Unusual pitch-up trim position has also been
a factor in some occurrences in other flight phases.
For more detailed analysis of the issues addressed by this proposal, please refer to the regulatory impact
assessment (RIA) Section 4.1.
2.2. What we want to achieve — objectives
The overall objectives of the EASA system are defined in Article 2 of the Basic Regulation. This proposal will
contribute to the achievement of the overall objectives by addressing the issues outlined in Chapter 2.1.
The specific objective is to mitigate the safety risk for large aeroplanes of loss of the normal G/A flight path, or
loss of control of the aircraft during G/A or other flight phases executed at low-speed, ensuring that:
— the design of large aeroplanes is such that the G/A procedure with all engines operating (AEO) can be
safely conducted by the flight crew without requiring exceptional piloting skill or alertness. The risk of
excessive crew workload and the risk of somatogravic illusion must be carefully evaluated, and design
mitigation measures must be put in place if those risks are too high;
— the design of large aeroplanes provides an adequate longitudinal controllability and authority during
G/A and other flight phases (focusing on low speed situations).
2.3. How we want to achieve it — overview of the proposals
It is proposed to amend CS-25, applicable to all new large aeroplane designs, in order to:
— Upgrade the assessment of the G/A manoeuvre and its procedure. The objective is to evaluate if the G/A
with AEO can be managed without creating excessive workload on the crew and without an excessive
risk of somatogravic illusion. When an unacceptable level of risk is identified, the applicant has to
implement design solutions to decrease this risk to an acceptable level. Implementing a reduced G/A
thrust function is one of the possible solutions which can be used, as it allows to provide more time to
the flight crew (on some two-engined aeroplanes it can range from 30 s to 1 min, assuming an average
2 000 ft/min rate of climb is maintained), and it decreases the dynamic of the manoeuvre, thus reducing
the flight crew workload and mitigating the risk of mis-management of the aeroplanes’ trajectory
(including the effect of somatogravic illusion). As other means may be proposed by industry, this is
considered as an acceptable means of compliance (AMC); the content of this AMC has been developed
based on the text of the EASA Special Condition used to certify this function on Airbus aeroplanes;
— Upgrade the existing certification specifications and acceptable means of compliance related to
longitudinal control and authority during G/A or other flight phases. For G/A, the aim is to demonstrate
adequate longitudinal controllability and adequate stall margin during transition from any approved
approach and landing configuration to G/A and up to the next flight phase and level-off (AEO and full
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 4 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
2. In summary: Why and what
thrust/power, different combinations of automatisms to be evaluated). For other flight phases, when
the aeroplane has an automatic pitch trim function, the stabiliser (or trim tab) travel should be limited
before or at stall warning activation to prevent excessive pitch trim such that it is possible to command a
prompt pitch down of the aircraft for control recovery.
2.4. What are the expected benefits and drawbacks of the proposals
The expected benefits and drawbacks of the proposal are summarised below. For the full impact assessment
of all options, please refer to Chapter 4.
The proposal would provide a fair safety benefit by requiring that all new CS-25 aeroplanes have design
features ensuring that managing a G/A manoeuvre does not create an unacceptable risk of loss of control of
the trajectory or loss of control of the aeroplane, including the risk of somatogravic illusion. Airbus, Boeing,
and Fokker already developed systems to reduce the thrust during G/A; these systems avoid applying
excessive thrust, thereby providing more time to the flight crew to perform the required action, and reduce
the dynamic of the flight phase which decreases both risks of excessive pitch attitudes and of somatogravic
illusion. Such a design improvement would also be required from other manufacturers developing aeroplanes
that can also present a similar level of risk. In addition, the proposal would require manufacturers to
investigate further the longitudinal controllability and authority in G/A and other flight phases, which would
contribute to mitigate the risk of upset attitudes and loss of control, in particular in relation with the effect of
the automatic pitch trim. The non-recurring cost (NRC) of this option is substantial for manufacturers that have
not yet developed a mitigation means like a reduced G/A thrust function, however, when included in the
development of an aeroplane, this is not significant relative to the overall cost of a development.
Operators/owners would not face, or only negligible, recurring cost (RC) associated with these design
improvements.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 5 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
3. Proposed amendments and rationale in detail
3. Proposed amendments and rationale in detail
The text of the amendment is arranged to show deleted text, new or amended text as shown below:
— deleted text is struck through;
— new or amended text is highlighted in grey;
— an ellipsis ‘[…]’ indicates that the rest of the text is unchanged.
3.1. Draft Certification Specifications (Draft EASA decision amending CS-25)
Amend CS 25.143 as follows :
CS 25.143 General
(See AMC 25.143)
(a) (See AMC 25.143(a) and (b)) The aeroplane must be safely controllable and manoeuvrable during–:
(1) Take-off;
(2) Climb;
(3) Level flight;
(4) Descent; and
(5) Landing Approach and go-around; and.
(6) Approach and landing.
(b) (See AMC 25.143(ab) and (b)) It must be possible to make a smooth transition from one flight condition
to any other flight condition without exceptional piloting skill, alertness, or strength, and without danger
of exceeding the aeroplane limit-load factor under any probable operating conditions, including: –
(1) The sudden failure of the critical engine. (See AMC 25.143(b)(1));
(2) For aeroplanes with three or more engines, the sudden failure of the second critical engine when
the aeroplane is in the en-route, approach, go-around, or landing configuration and is trimmed
with the critical engine inoperative; and
(3) Configuration changes, including deployment or retraction of deceleration devices.; and
(4) Go-around manoeuvres with all engines operating. The assessment must include, in addition to
controllability and manoeuvrability aspects, the flight crew workload and the risk of somatogravic
illusion (See AMC 25.143(b)(4)).
Create a new AMC 25.143(b)(4) as follows:
AMC 25.143(b)(4)
Go-around manoeuvres
1. Background
When full thrust or power is applied during a go-around, an excessive level of performance (rate of climb,
accelerations) may be reached very quickly and may make it difficult for the flight crew to undertake the
actions required during a go-around, especially in a constrained (air traffic control instructions, operational
procedure) and rapidly changing environment.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 6 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
3. Proposed amendments and rationale in detail
This level of performance can also generate acceleration levels (in particular forward linear accelerations) that
could lead to spatial disorientation for the flight crews (e.g. somatogravic illusion), in particular when
combined with reduced visibility conditions.
Accidents and incidents have occurred during or after go-around where somatogravic illusions have led flight
crews to make inappropriate nose-down inputs, leading to an aircraft upset, a loss of control, or a loss of the
normal go-around flight path, and, in some cases, controlled flight into terrain with catastrophic
consequences.
Other accidents resulting in loss of control were due to excessive pitch attitudes combined with a lack of crew
awareness.
The risk is higher on two-engined aeroplanes because of their higher level of performance (thrust over weight
ratio), but it should also be considered on other types of aeroplanes.
2. Criteria for assessing the Go-around manoeuvre risk with respect to somatogravic illusion and flight crew
workload
2.1 Somatogravic illusion
It is considered that the risk of somatogravic illusion is high when combining high values of pitch-up angle,
pitch rate, and longitudinal acceleration, together with a loss of outside visual reference.
2.2 Workload
In order to provide sufficient time to the flight crew for managing their tasks, and, therefore, keep the
workload at a reasonable level, longitudinal acceleration and vertical speed should be constrained.
2.3 Mitigation means
Accordingly, the applicant should propose a specific mitigation means in case any of the following conditions
can be encountered during a go-around manoeuvre:
— pitch rate value above 4 degrees per second;
— pitch-up attitude above 20 degrees;
— longitudinal acceleration above 3,7 km/h (2 kt) per second;
— vertical speed above 3 000 ft/min; and
— climb gradient above 22 %.
Note: Exceptions may be made for emergency scenarios.
The proposed mitigation means should:
— provide a robust method to reduce the risk identified (i.e. maintain the above parameters within a
reasonable range of values); and
— be used during standard go-around procedure.
A reduced go-around thrust or power function is considered as an acceptable mitigation means (refer to
Chapter 4 below).
3. Go-around scenarios to be evaluated
It is recommended to perform in flight a go-around manoeuvre with all-engines-operating (AEO) as per the
standard procedure:
— with the most unfavourable and practicable combination of centre of gravity position and weight
approved for landing,
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 7 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
3. Proposed amendments and rationale in detail
— with any practicable combination of Flight Guidance/Autothrust-throttle/Autopilot to be approved,
including manual,
— with a level-off altitude 1 000 ft above the go-around initiation altitude,
in order to assess the following:
pitch controllability (see also CS 25.145(f) and related AMC);
speed control capability;
flight crew workload (task management in a changing environment); and
the risk of somatogravic illusion.
4. Implementation of a reduced go-around (RGA) thrust or power function
A RGA thrust or power function may be provided such that, when a go-around is initiated with any practicable
combination of Flight Guidance/Autothrust-throttle/Autopilot modes, including manual, the engine thrust or
power applied is limited to maintain the performance of the aeroplane (in particular its rate of climb) at a level
which is compatible with the flight crew workload during this phase, and in order to reduce the risk of
somatogravic illusion for the flight crew.
This thrust or power reduction function may be available either through aircraft systems automatism or
manually.
In any case, an acceptable procedure should be available in the Aeroplane Flight Manual (AFM).
4.1 Design target
RGA functions implemented by some manufacturers with a design target of 2 000 ft/min rate of climb
capability have been accepted by EASA.
4.2 Cockpit indications
The following information should be indicated to the flight crew:
— the active thrust or power mode (RGA or full thrust or power); and
— in RGA mode, the level of thrust or power targeted by the system.
Thrust level tables should be provided in the AFM for manual go-around.
4.3 Evaluation
An evaluation of the go-around manoeuvre with the RGA thrust or power function should be conducted
following the recommendations of Chapter 3 above.
4.4 Thrust or power mode command
It should be possible for the flight crew, at any time and without delay, to select and apply the full go-around
thrust or power.
The applicant should include specific procedures for which full thrust or power may be required, such as
windshear alert procedures, TCAS alert procedures, etc.
4.5 Engine failure during go-around with RGA thrust or power
When an engine failure occurs during a go-around performed with active RGA thrust or power and if the
required thrust or power from the remaining engine(s), to achieve adequate performance level, cannot be
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 8 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
3. Proposed amendments and rationale in detail
applied automatically, a warning alert to the flight crew is required to trigger the thrust or power recovery
action.
The procedure for recovery of the engine thrust or power setting must be demonstrated as acceptable in
terms of pilot detection and required action in high workload environment.
The following items should be evaluated:
— assess the timeliness of minimum performance achievement;
— flight crew awareness (indication, alerting…);
— flight crew actions (command); and
— flight crew workload in general.
4.6 Performance published in the AFM for RGA thrust or power
It is reminded that approach climb (one-engine-inoperative) performance and landing climb (all-engines-
operating) performance tables published in the AFM shall take into account the actual behaviour of thrust or
power management in go-around.
Amend CS 25.145 as follows:
CS 25.145 Longitudinal control
(See AMC 25.145)
(a) (See AMC 25.145(a)) It must be possible at any point between the trim speed prescribed in CS
25.103(b)(6) and stall identification (as defined in CS 25.201(d)), to pitch the nose downward so that the
acceleration to this selected trim speed is prompt with –
(1) The aeroplane trimmed at the trim speed prescribed in CS 25.103(b)(6);
(2) The most critical landing gear extended configuration;
(3) The wing-flaps (i) retracted and (ii) extended; and
(4) Engines thrust or Ppower (i) off and (ii) at go-around setting. maximum continuous power on the
engines.
(…)
(f) It must be possible to maintain adequate longitudinal and speed control under the following conditions
without exceptional piloting skill, alertness, or strength, and without danger of exceeding the aeroplane
limit-load factor and while maintaining adequate stall margin throughout manoeuvre:
(1) Starting with the aeroplane in each approved approach and landing configuration, trimmed
longitudinally, and with thrust or power setting per CS 25.161(c)(2), perform a go-around,
transition to the next flight phase and make a smooth level-off at the desired altitude:
(i) with all engines operating and the thrust or power controls moved to the go-around power
or thrust setting;
(ii) with the configuration changes, as per the approved operating procedures or conventional
operating practices; and
(iii) with any practicable combination of Flight Guidance/Autothrust-throttle/Autopilot to
be approved, including manual.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 9 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
3. Proposed amendments and rationale in detail
(2) Reasonably expected variations in service from the established approach, landing, and go-around
procedures for the operation of the aeroplane (such as under or over-pitch angle target during
the go-around and adverse trim positions) may not result in unsafe flight characteristics.
Amend AMC 25.145(a) as follows:
AMC 25.145(a)
Longitudinal Control – Control Near The Stall
1. CS 25.145(a) requires that there be adequate longitudinal control to promptly pitch the aeroplane nose
down from at or near the stall to return to the original trim speed. The intent is to ensure sufficient pitch
control for a prompt recovery if the aeroplane is inadvertently slowed to the point of the stall. Although
this requirement must be met with engines thrust or power off and at go-around setting maximum
continuous power, there is no intention to require stall demonstrations at engine thrusts or powers
above that specified in CS 25.201(a)(2). Instead of performing a full stall at maximum continuous power
go-around thrust or power setting, compliance may be assessed by demonstrating sufficient static
longitudinal stability and nose down control margin when the deceleration is ended at least one second
past stall warning during a 0.5 m/s2 (one knot per second) deceleration. The static longitudinal stability
during the manoeuvre and the nose down control power remaining at the end of the manoeuvre must
be sufficient to assure compliance with the requirement.
2. The aeroplane should be trimmed at the speed for each configuration as prescribed in CS 25.103(b)(6).
The aeroplane should then be decelerated at 0.5 m/s2 (1 knot per second) with wings level. For tests at
idle thrust or power, it should be demonstrated that the nose can be pitched down from any speed
between the trim speed and the stall. Typically, the most critical point is at the stall when in stall buffet.
The rate of speed increase during the recovery should be adequate to promptly return to the trim point.
Data from the stall characteristics test can be used to evaluate this capability at the stall. For tests at
maximum continuous power go-around thrust or power setting, the manoeuvre does not need not to be
continued for more than one second beyond the onset of stall warning. However, the static longitudinal
stability characteristics during the manoeuvre and the nose down control power remaining at the end of
the manoeuvre must be sufficient to assure that a prompt recovery to the trim speed could be attained
if the aeroplane is slowed to the point of stall.
3. For aeroplanes with an automatic pitch trim function (either in manual control or automatic mode), the
nose-up pitch trim travel should be limited before or at stall warning activation to prevent excessive
nose-up pitch trim position such that it is possible to command a prompt pitch-down of the aeroplane
for control recovery.
The applicant may account for certain flight phases where this limit is not appropriate and provide
rationale supporting theses exceptions to EASA for consideration.
The applicant should demonstrate this feature by flight test or with a validated simulator.
Normal and degraded flight control laws resulting from failure cases should be considered for this
evaluation in conjunction with CS 25.1309 and CS 25.671.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 10 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
3. Proposed amendments and rationale in detail
Create a new AMC 25.145(f) as follows:
AMC25.145(f)
Longitudinal control – Go-around
1. CS 25.145(f)(1) requires that there be adequate longitudinal control to promptly pitch the aeroplane
(nose down and up) and adequate speed control in order to follow or maintain the targeted trajectory
during the complete manoeuvre from any approved approach and landing configuration to a go-around
transition to the next flight phase and make a smooth level off at the desired altitude.
The evaluation should be performed throughout the range of thrust-to-weight ratio to be certified,
including in particular the highest thrust-to-weight ratio for the all-engines-operating condition
(aeroplane at its minimum landing weight, all engines operating and the thrust or power at the go-
around setting) and show adequate pitch control (no risk of excessive pitch rate or attitude, maintain
adequate stall margin throughout the manoeuvre, no overshoot of the level off altitude) and adequate
speed control (no risk of speed instability or exceedance of VFE with the wing-flaps extended and VLE
with the landing gear extended).
2. Reasonably expected variations in service from established approach, landing and go-around procedures
shall be evaluated and must not result in unsafe flight characteristics.
This should include go-arounds during certification flight and simulator test programmes with combined
effects of thrust or power application and nose-up trim pitching moment. This means, for an aeroplane
with low engines (i.e. installed below the aeroplane centre of gravity),:
a) with the most unfavourable combination of centre of gravity position and weight approved for
landing;
b) all engines operating and the thrust or power controls set to the (max) go-around thrust or power
setting; and
c) longitudinal control trimmed, as follows:
i) in manual mode with a manual pitch trim, a pitch trim positioned for the approach or
landing configuration, and kept at this position during the go-around phase; or
ii) in autopilot or manual mode with an automatic pitch trim function: the most adverse
position that can be sustained by the autopilot or automatic pitch trim function, limited to
the available protecting/limiting features or alert (if credit can be taken from it).
Amend AMC 25.201(d) as follows:
AMC 25.201(d)
Stall Demonstration
1. The behaviour of the aeroplane includes the behaviour as affected by the normal functioning of any
systems with which the aeroplane is equipped, including devices intended to alter the stalling
characteristics of the aeroplane.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 11 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
3. Proposed amendments and rationale in detail
2. Unless the design of the automatic flight control system of the aeroplane protects against such an event,
the stalling characteristics and adequacy of stall warning, when the aeroplane is stalled under the
control of the automatic flight control system, should be investigated. (See also CS 25.1329(f g).)
Amend Appendix Q as follows:
Appendix Q
Additional airworthiness requirements for approval of a Steep Approach Landing (SAL) capability
(See AMC to Appendix Q)
(…)
(SAL) 25.5 Safe operational and flight characteristics
(…)
(e) All-engines-operating steep approach.
It must be demonstrated that the aeroplane can safely transition from the all-engines-operating steep
landing approach to:
(1) the all-engines-operating approach climb configuration; and
(2) the one-engine-inoperative approach climb configuration with one engine having been made
inoperative,
for the following conditions:
(1i) The selected steep approach angle;
(2ii) An approach speed of VREF(SAL);
(3iii) The most critical weight and centre of gravity; and
(4iv) For propeller-powered aeroplanes, the propeller of the inoperative engine shall be at the
position it automatically assumes following an engine failure at high power.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 12 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
4. Impact assessment (IA)
4.1. What is the issue
A number of accidents or serious incidents with commercial air transport large aeroplanes occurred either
during/at the end of a go-around phase, or with the aeroplane close to the ground (but not in go-around
mode) and with the pilots attempting to climb. A loss of the normal go-around flight path or loss of control of
the aircraft has been observed in relation to inadequate flight crew awareness of the aeroplane’s state, or
inadequate management by the flight crew of the relationship between pitch attitude and thrust. Unusual
pitch-up trim position has also been a factor in some occurrences in other flight phases.
The focus of this NPA is on two main issues:
1. Go-around management issue
Difficulties encountered by flight crews to manage the go-around manoeuvre mainly due to the high level of
aeroplane performance and to the limited available pitch authority.
2. Unusual pitch-up trim position in other flight phases
In some occurrences, unusually high pitch-up trim position observed during other flight phases at low speed
(typically at or close to the stall speed) contributed to a loss of control or non-recovery after a stall.
The BEA study (ASAGA)
The above-mentioned occurrences led the French Bureau d’Enquêtes et d’Analyses pour la sécurité de
l’aviation civile (BEA) to conduct the ASAGA5 study in order to analyse this category of events (the so-called
ASAGA-type events) and to identify the causal factors which contributed to such events and to suggest
potential action to prevent them from reoccurring.
The first phase of the BEA work was to conduct a statistical study, primarily of the data provided by the BEA
and the International Civil Aviation Organization (ICAO). During the second phase of the study, significant
events were selected and analysed. Subsequently, a survey was addressed to airline pilots, and Boeing 777 and
Airbus A330 simulator sessions were performed.
A number of factors contributed to the ASAGA-type accidents and serious incidents, as well as to the
difficulties experienced by flight crews performing go-arounds or climbs close to the ground, in real operation
or in the simulator. Among these factors, two key items linked to the design or ergonomics of the aeroplanes
contribute significantly to the loss of the normal go-around flight path:
— somatogravic illusions related to excessive thrust; and
— non-detection of the position of nose-up trim by the flight crew.
This led the BEA to address the following safety recommendations to EASA in the domain of ergonomics and
certification.
Limitations on available thrust
5
Study on Aeroplane State Awareness during Go-Around (ASAGA), published in August 2013. The report is available on the Bureau d’Enquêtes et
d’Analyses pour la sécurité de l’aviation civile (BEA) website at https://www.bea.aero/en/safety-studies/access-to-studies/aeroplane-state-
awareness-during-go-around/.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 13 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
When full thrust is applied during a go-around, an excessive climb speed can be reached very quickly, thus
making it difficult for flight crews to perform the actions related to the go-around procedure. Firstly, it can be
incompatible with the time required to perform the go-around and, secondly, it can be a source of the
somatogravic illusions that have led flight crews to make inappropriate nose-down inputs. Certain
manufacturers have already implemented a system limiting the thrust. The main objective is to give flight
crews sufficient time to limit excessive sensory illusions and excessive pitch attitudes.
Consequently, the BEA recommends that:
— EASA, in coordination with major non-European aviation authorities, amends the CS-25 provisions so
that aircraft manufacturers add devices to limit thrust during a go-around and to adapt it to the flight
conditions. [Recommendation FRAN-2013-025]
— EASA examines, according to type certificate, the possibility of retroactively extending this measure in
the context of PART 26 / CS-26, to the most high performance aircraft that have already been certified.
[Recommendation FRAN-2013-026]
Go-around and position of pitch trim
A go-around performed at low speed with an unusual nose-up trim position can lead to a stall and loss of
control. Before the go-around, the speed drops and the aircraft systems compensate for this loss of speed by
pitching up the stabiliser more and more.
Consequently, aircraft manufacturers should develop means to prevent this type of excessive trim from
occurring and/or to prevent the aircraft stabiliser from being kept in an unusual attitude during a go-around.
Flight crews pay less and less attention to the position of the trim during flight. They should thus be informed
as early as possible of an excessive drop in speed so that they avoid applying full thrust with an unusual
position of the pitch-up trim.
In the event of an excessive nose-up pitch position that is uncontrolled, few pilots know the upset recovery
procedure which consists of reducing the thrust and/or modifying the trim position.
Consequently, the BEA recommends that:
— EASA, in cooperation with the major non-European certification authorities, make mandatory the
implementation of means to make crews aware of a low speed value and, where necessary, prevent an
unusual nose-up trim position from occurring or being maintained. [Recommendation FRAN-2013-042]
Somatogravic illusion during go-around
The Rulemaking Group (RMG) of RMT.0647 decided to investigate the available scientific knowledge on spatial
disorientation of flight crews, in particular the case of somatogravic illusion. The goal was to understand what
are the parameters that can trigger or influence spatial disorientation during go-around, in order to determine
how to mitigate the risk at design level.
General description of the somatogravic illusion
It is the result of a misinterpretation of a very noticeable sensation related to linear acceleration. This illusion
typically occurs on a go‐around when the aeroplane transitions from a slowing down to a rapid acceleration
and pitch‐up. The vestibular system cannot distinguish between an inertial acceleration and a component of
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 14 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
gravity, and the rapid acceleration can be misinterpreted as a further pitching-up moment. Instrument
meteorological conditions (IMC) and/or darkness contribute by removing valid visual inputs. In these
conditions, a pilot may perceive the linear acceleration during the go-around as (over-)pitching of the
aeroplane and may start to push the nose downward to compensate. This can result in an actual nose‐down
attitude and descent toward the ground.
Human models
In the area of vestibular research, studies have been performed to model the somatogravic illusion. In
particular the work from Jenks Vestibular Physiology Laboratory, Massachusetts Eye and Ear Infirmary
(D.M. Merfeld) is noticeable as they provided, already since early 2000, human models which have then be
used in following projects to simulate vestibular illusions, including the somatogravic illusion. The models
mimic human responses to a number of different paradigms, ranging from simple paradigms, like roll tilt, to
complex paradigms, like post-rotational tilt and centrifugation.
The RMG liaised with TNO, as well as the BEA (who developed simulation tools based on the Merfeld’s model).
TNO simulation tool
The Netherlands Organisation for Applied Scientific Research (TNO) has more than 20 years of experience in
research and training with respect to spatial disorientation. For this, TNO employs the DESDEMONA simulator
(acronym for DESorientation DEMONstrAtor), a flight simulator with a special moving base, including a
centrifuge, which enables the reproduction of spatial disorientation illusions. This simulator can be used for
both research and training of complex situations, which typically lead to controlled flight into terrain (CFIT), or
loss of control in flight (LOC-I). TNO had a leading role in the FP‐7 project SUPRA (simulation of upset recovery
in aviation).
TNO developed, in cooperation with Boeing, a spatial disorientation identification tool, SDiT (see paper of
Mumaw et al)6. The model consists of transfer functions of vestibular and visual system. The inputs are the
aeroplane’s 3 degrees of freedom of rotation velocities, and 3 degrees of freedom gravito-inertial
accelerations (e.g. from the flight data recorder (FDR) recording). The outputs are the perceived
3 accelerations, perceived 3 orientation angles (pitch, roll and yaw), and perceived angular velocities. It can
flag vestibular illusions: somatogyral illusions, somatogravic illusions. The tool was validated in several flight
tests with non-biased subjects that were given reduced visual references. In addition, full motion including
sustainable G-loading (6-deg of freedom) simulator experiments were performed in DESDEMONA to compare
the model’s prediction with the responses of volunteers (for example, Nooij and Groen, 2011)7. These studies
confirmed the model prediction, and also showed that there are variabilities between individuals.
An ATPL pilot and member of the RMG participated in an experimental analysis of G/A scenarios with the
support of SDiT, in a fixed-base flight simulator. Two Boeing 737 flight profiles were simulated and then
analysed with the SDiT. In both cases the G/A was performed with autopilot engaged.
— The first profile represented a G/A with limited performance: the mass/thrust ratio was set at a fairly
high level, taking a gross weight (GW) of 66t and applying reduced G/A thrust. A few seconds after the
rotation, the autopilot progressively reduces the pitch angle to allow airspeed increase. Initially, the
6
Mumaw, R.J., Groen, E.L., Fucke, L., Houben, M., Bos, J.E. (2016) A new tool for analyzing the potential influence of vestibular illusions. ISASI Forum,
Journal of the International Society of Air Safety Investigators 49, 6-12.
7
Nooij, S.A.E..& Groen, E.L. Rolling into spatial disorientation: simulator demonstration of the post-roll (Gillingham) illusion. Aviat. Space Environ.
Med. 82, 505-512 (2011).
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 15 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
perceived pitch and real pitch angles are consistent while the longitudinal (or ‘linear’) acceleration
decreases. But when the longitudinal acceleration increases again, then the perceived pitch angle
increases although the real pitch angle continues to decrease. This shows a potential risk of spatial
disorientation. See the figure below:
Legend: Full lines represent the actual values; dashed lines represent the perceived values.
— The second profile represented a G/A with higher performance: the mass/thrust ratio was set at a low
level, taking a GW of 55t and applying full G/A thrust. In this case, after the rotation there is no pitch
reduction applied by the autopilot (because of the highest performance). However, after some time, the
perceived pitch angle increases while the real pitch angle starts to decrease. A potential risk of
somatogravic illusion is thus evidenced also in this case. Furthermore, this situation is maintained over a
longer time period (more than 25 seconds) than in the reduced G/A thrust case above (approx.
15 seconds). See the figure below:
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 16 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
Legend: Full lines represent the actual values; dashed lines represent the perceived values.
Keeping in mind the limitations of this experiment (flight data from a fixed simulator processed through a tool
simulating the somatogravic illusion), the analysis of the two cases concluded that:
— a situation where the perceived pitch angle diverges and becomes higher than the real pitch angle
appears in both cases;
— the maximum reached delta (perceived pitch – real pitch) is similar in both cases;
— however, in the case of the full G/A thrust:
the linear acceleration is higher;
the situation of mismatch between perceived and real pitch is maintained over a longer time
period.
BEA simulation tool
The BEA based their model on the Merfeld’s model, and used it during investigation of accidents or incidents,
together with FDR/CVR recordings, to evaluate perceptual illusions and spatial disorientations (in particular,
for events where reduced or no visibility is involved or where the pilots do not monitor the PFD).
The input and output parameters are equivalent to the TNO model.
The capacity of the tool was illustrated taking the case of the A330 Tripoli accident. The BEA simulation clearly
shows a divergence between the perceived pitch angle and the actual pitch angle during the go-around phase,
as shown on the graph below:
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 17 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
Overall conclusion
The somatogravic illusion is created by a combination of linear acceleration, gravitational acceleration, and
rotation rate. Human body sensors can convert a high linear acceleration and rotation rate into an apparent
pitch angle that is significantly higher than the actual one. The duration of the acceleration is a key factor.
Experimental analysis show that reducing the G/A thrust does not necessarily prevent the somatogravic
illusion. However, reducing the thrust reduces the linear acceleration and the maximum perceived pitch which
should mitigate the onset of the somatogravic illusion. There is also a variability of pilots sensitivity which is a
function of different factors like physiology, workload and fatigue.
Additional studies may be performed to further investigate and compare the somatogravic illusion effects
perceived during real flight vs. what is perceived on a full flight simulator (FFS). Depending on the type of
aeroplane and the FFS used, there may be different results. For a given type of aeroplane, there may be
differences between a FFS flight and a real flight, therefore. the risk of negative training should be considered.
Analysis of occurrences relevant to RMT.0647
A selection of occurrences relevant to the terms of reference (ToR) RMT.0647 was performed by the RMG. An
analysis was performed by the RMG and its outcome is summarised below.
The occurrences are listed in Appendix 1 to this NPA. A short narrative is included.
As required in the ToR, two categories of occurrences were gathered and analysed:
— Category 1: occurrences during or after a go-around where a loss of the normal go-around flight path, or
loss of control of the aircraft, without being caused by a technical failure on the aircraft or other
abnormal external factors (collision, storm, etc.). The RMG considered as candidate the events identified
by the BEA in their ASAGA study report, plus other relevant events found.
— Category 2: occurrences where an unusual pitch-up trim position, combined with high-thrust
application, occurred in other flight phases, such as during a transition from descent to climb, or in
cruise after an abnormal event leading to stall or close-to-stall speed situation requiring a recovery
action by the pilots.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 18 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
Category 1 occurrences analysis:
25 go-around related occurrences were identified. Refer to Appendix 1 for the list and narrative of
occurrences.
Out of the 25 occurrences (12 accidents and 13 incidents):
— Contributing factors:
High thrust application is involved in 16 occurrences (8 accidents and 8 incidents or serious
incidents),
Spatial disorientation in the form of somatogravic illusion is identified as probable factor in 9
occurrences (7 accidents and 2 serious incidents),
A pitch trim position at, or close to, the full nose‐up position is involved in 7 occurrences
(3 accidents and 4 incidents or serious incidents).
— Potential mitigating factors:
11 occurrences (5 accidents and 6 incidents or serious incidents) could possibly have been
mitigated to a certain extent by a reduced G/A thrust function,
6 occurrences (2 accidents and 4 incidents or serious incidents) could possibly have been
mitigated by a means to limit or correct the pitch trim travel at low speed,
3 occurrences (1 accident and 2 serious incidents) would have been mitigated by compliance of
the aeroplane design with the current CS 25.1329(h) specifications on low airspeed protection,
2 occurrences (1 accident, 1 incident) would have been mitigated by compliance of the aeroplane
design with the current CS 25.1329(l) specifications related to the autopilot behaviour.
There are, nevertheless, 10 occurrences for which the group did not identify design mitigation means. These
are cases where the human factors contribution was too high. Such occurrences can, nevertheless, be
mitigated by other means, like upgrade of pilots training on the conduct of G/A (with full thrust/light weight,
as well as with reduced thrust when the function is available), CRM training and implementation, fatigue
management, improvement of G/A published procedures, etc.
The RMG also noted that in 4 occurrences (2 accidents and 2 incidents) on Boeing aeroplanes, a reduced go-
around function was available and used during these events; somatogravic illusion is a probable factor of the
2 accidents (Kazan and Osh), and it is also a suspected factor for the two incidents. This shows that limiting the
thrust does not necessarily allow to prevent a go-around related occurrence.
In term of aeroplane types, mainly Airbus and Boeing types are represented in these occurrences:
— 12 Airbus (6 A300/A310, 4 A319/A320, 2 A330);
— 10 Boeing (2 B737-300, 3 B737-500, 1 B737-800, 2 B757-200, 2 B777);
— 1 Mc Donnell Douglas DC-8-63;
— 1 Swearingen SA226 TC Metro II (small aeroplane)
— 1 Bombardier DHC-8-103.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 19 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
Category 2 occurrences analysis:
4 occurrences were identified. Refer to Appendix 1 for the list and narrative of occurrences.
These 4 fatal accidents could have benefited from a means to limit or correct the pitch trim travel at low
speed. However, for 3 of these accidents, due to the other contributing factors of these events, this would
probably have not prevented the accident.
Questionnaire sent to manufacturers of large aeroplanes
In order to seek the view of, and information from, other manufacturers not represented in the RMG, a
questionnaire was sent to 12 CS-25 aeroplane manufacturers8.
The inputs provided by the responses represent an important source of information for several sections of the
impact assessment, including the problem definition, the options, and its analysis.
The questionnaire included:
— General questions on the difficulties faced by pilots during G/A, features available on their design to
reduce and adapt the thrust during G/A, to limit the pitch trim position during G/A or other flight phases
at low speed;
— Detailed questions on G/A thrust reduction systems in the fields of: status of implementation on the
different types owned, cost impacts, issues encountered during the development, function benefits, and
availability.
— Detailed questions on automatic pitch trim control systems in the fields of: status of implementation on
the different types owned, presence of a travel limitation function at low speed, function availability,
and presence of an alerting function.
10 manufacturers out of 12 replied (83 %).
A summary of the responses received is provided in Appendix 2 to this NPA.
These responses show that the difficulties encountered by the flight crews during G/A are more important on
twin-turbofan airliners with engines mounted under the wings. The risk of somatogravic illusion is higher
there. They also provide the opinion that better training of pilots to conduct a G/A is paramount, as well as the
training to recognise and mitigate a somatogravic illusion.
Three of the respondent manufacturers (Airbus, Boeing and Fokker) have developed a reduced G/A thrust
function, implemented on some of their aeroplanes, to mitigate the issues faced during G/A which are not
limited to the somatogravic illusion, but also include the very limited time to perform all the actions required
during G/A and the non-compatibility with the published G/A procedures (e.g. level-off altitude).
8
Airbus, Boeing, Bombardier, Dassault, Gulfstream, ATR, Textron Aviation, Fokker, Sukhoi, Saab, Embraer, Learjet
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 20 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
4.1.1. Safety risk assessment
The application of excessive engine thrust/power during G/A, possibly combined with a pitch-up trim
configuration, can lead to a loss of the normal G/A flight path or stall of the aeroplane if the pilots do not react
on time to reduce the thrust and adjust the position of the trim.
Furthermore, the application of high thrust, possibly combined with a low aeroplane weight (e.g. at the end of
a flight), can lead to a very high level of performance which is not adapted to the go-around phase: this leaves
the pilots very limited time to cope with the actions required during this phase and thereby creates a high
peak of workload. It is also often not compatible with the go-around procedure, in particular the level-off
altitude. This increasing stress put on the pilots, combined with the dynamic of the flight phase, the eventual
absence of visual references and surprise effects (e.g. orders from the ATC) are factors increasing the risk of
somatogravic illusion.
As this kind of manoeuvre typically occurs close to the ground, there is a high risk of catastrophic
consequences from the impact with the ground surface or constructions. The risk is higher for two-engined
aeroplanes with wing-mounted engines, as demonstrated by the review of accidents and incidents. This is
because two-engined aeroplanes have a higher amount of thrust/power in AEO configuration in order to
comply with the performance certification specifications applicable to the OEI configuration. Wing-mounted
engines also generate a higher pitch-up moment when thrust is applied.
Furthermore, the risk of reaching a loss-of-control situation because of unusual pitch-up trim position
combined with high-thrust application also exists in other flight phases like during a transition from descent to
climb, or in cruise after an abnormal event leading to stall or close-to-stall speed situation requiring a recovery
action by the pilots.
4.1.2. Who is affected
Large aeroplane manufacturers, operators, and pilots of large aeroplanes are affected by this issue.
4.1.3. How could the issue/problem evolve
Go-around management issue
Almost all the reported occurrences involved Airbus and Boeing types of aeroplanes. Out of the three
occurrences involving other types and reviewed by the RMG, only one of them could have potentially been
mitigated by a design improvement (i.e. a thrust reduction system).
Both Airbus and Boeing have already developed a reduced G/A thrust function which adapts the thrust in
order to reach and follow some G/A performance parameters. This is considered as a proactive action which
provides safety improvement by making the G/A more manageable: this helps the pilots for the management
of the thrust and pitch attitude relationship, and this provides more time to conduct all the required actions of
the G/A procedure.
In the case of Boeing, ‘reduced go-around thrust functions’ are installed on all current production aircraft and
installed on some of the older models. Here is an overall status of the Boeing fleet:
— Boeing 737: 737-300 through 737-900 are equipped with the function, as well as the new
737 MAX. The last couple of hundred 737-200’s are equipped, but the remainder of 737-100 and
737-200 are not.
— Boeing 757, 767, 777, 787 are equipped.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 21 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
— Boeing 747: 747-400 is equipped. 747-100 through 747-300 models are not all equipped (i.e. mixed
fleet situation: some aeroplanes are equipped with a reduced go-around thrust function and the
others are not equipped).
— Boeing 707, 727, DC-8, DC-9, DC-10, MD-80, MD-11 are not equipped.
Boeing, in cooperation with the European Commercial Aviation Safety Team (ECAST), also communicated on
how to perform safe G/A manoeuvres, highlighting the difficulties which may be faced and how to handle
them9.
Concerning Airbus, modifications have been developed in the last years, starting with an implementation on
the most recent types (A380 and A350 aircraft are all equipped now). It is now being implemented on the
A320 family NEO and the A330 (CEO, and in the future NEO). Nevertheless, operators of these A320 family and
A330 aeroplanes can choose to activate the option or not, for example, based on fleet mixability strategy. Only
the A300/A310, the A320 family CEO, and the A340 types will not receive this function because of
considerations including technical feasibility at a reasonable cost, fleet size and usage, out-of-production
status, and criticality of the climb capability. To mitigate the risk on these aeroplanes, Airbus performed
several activities:
—Advertisement of the ‘TOGA then reduction to CLB’ procedure to A320 family customers,
—Safety recommendations/reminder of good practices widely communicated within airline operators10.
As part of it, a specific briefing for the G/A technique to be applied is recommended prior to each
approach.
Therefore, various aeroplanes in the most-at-risk category (aeroplanes with two wing-mounted engines) are,
or will soon be, equipped with a reduced G/A thrust function which should provide a safety improvement in
the next years.
This safety benefit is, nevertheless, difficult to quantify and it should be kept in mind that accidents/incidents
occurred when the function was used (on Boeing aeroplanes). Therefore, other action must be taken to
mitigate the risk of loss of the normal go-around flight path or loss of control of the aircraft during G/A.
Another manufacturer, Fokker, has also developed a function which mitigates the risk of the G/A manoeuvre.
The function, implemented on Fokker 70/100 aeroplanes (tail mounted twin turbofan), allows to maintain a
safe pitch attitude and can reduce the thrust in order to limit the rate of climb to a reasonable value while
following a target airspeed.
EASA evaluated the proportion of large aeroplanes (operated by EASA Member States operators in commercial
air transport) that are equipped with a system reducing the G/A thrust.
The goal is to provide orders of magnitude on the level of equipment today and in the future, assuming that
the number of manufacturers and types of aeroplanes remain as they are today. This provides a view on the
9
Boeing AERO magazine 03Q2014, see article entitles ‘Performing Safe Go-Around Maneuvers’:
http://www.boeing.com/commercial/aeromagazine/articles/2014_q3/pdf/AERO_2014q3.pdf
10
Airbus Flight Operations Briefing Notes – Approach Techniques - Aircraft Energy Management during Approach:
http://skybrary.aero/bookshelf/books/166.pdf
Airbus Flight Operations Briefing Notes – Descent management - Being Prepared for Go-Around:
http://skybrary.aero/bookshelf/books/2272.pdf
Airbus Safety First Magazine #23, January 2017, page 14 (‘Introduction to the Soft Go-Around’):
http://www.airbus.com/company/aircraft-manufacture/quality-and-safety-first/library/
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 22 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
evolution of the fleet, if no action is taken, to change the current situation (either from rulemaking or from
industry self-initiative).
Appendix 3 provides the details on how this evaluation has been performed, including the assumptions made.
The evaluation concludes that:
— for the current fleet of in-service aeroplanes: 24.8 % of the aeroplanes are equipped,
— for the future aeroplanes to be manufactured and put into service within the next 2 years: 48.3 %
of the aeroplanes will be equipped, and
— for the future fleet of aeroplanes: the proportion aeroplanes equipped will gradually increase from
24.8 % to reach 48.3 % in 2041.
EASA has taken action to reinforce the G/A training requirements for pilots. SIB No 2014-09 ‘Aeroplane Go-
around Training’ was published in 201411. Rulemaking task RMT.0581 on ‘Loss of Control Prevention and
Recovery Training’ is active and aims at ensuring a better initial and recurrent training on the conduct of a G/A
procedure12; the different possible configurations should be addressed from the one-engine-operative to the
all-engine-operative/full thrust configurations, and also the training to use the reduced G/A thrust function
when available. The somatogravic illusion will also be trained so that pilots are better able to recognise and
react to it. These activities are considered paramount to improve the safety level in the future.
EASA is also working on regulatory measures limiting modifications to published missed-approach procedures,
which is an additional element of risk for inadequate management of the go-around, as illustrated for instance
in the BEA ASAGA study. This is being addressed within the framework of RMT.0464 ‘Requirements for air
traffic services’. The first deliverable, a notice of proposed amendment, NPA 2016-09(B)13, was published on
14 September 2016 and the consultation period, after being extended, ended on 28 February 2017.
Based on the above, it is concluded that in the absence of a regulatory action dealing with design
requirements related to the G/A management, the proactive actions taken by Airbus and Boeing should
contribute, together with other important efforts made to improve pilot training and missed-approach
procedure management, to an improvement of the overall safety level during G/A for many of the most-at-risk
aeroplanes and operations.
However, other new aeroplanes could benefit from design mitigation means allowing to limit the performance
of the aeroplane and provide more time to the flight crew to conduct the G//A manoeuvre. These new
aeroplanes may also have design and performance characteristics putting them in the category of aeroplanes
at a higher risk in terms of G/A management. If no regulatory action is taken, it may be that these new
aeroplanes are not equipped with design mitigation means (such as a G/A thrust reduction function) and
could, therefore, lead to incidents or accidents.
11
EASA Safety Information Bulletin 2014-09 dated 08 April 2014, ‘Aeroplane Go-Around Training’, available at: http://ad.easa.europa.eu/ad/2014-09
12
ED Decision 2015/012/R of 4 May 2015 amending the Acceptable Means of Compliance and Guidance Material to Part-Definitions and Part-ORO of
Regulation (EU) No 965/2012;
NPA 2015-13 Loss of control prevention and recovery training (https://www.easa.europa.eu/document-library/notices-of-proposed-
amendment/npa-2015-13), which will be followed in 2017 by an Opinion to the European Commission for an amendment of Commission Regulation
(EU) No 1178/2011, and later on by an EASA Decision containing related Acceptable Means of Compliance (AMC) and Guidance Material (GM).
13
The NPA includes proposals to establish a detailed regulatory framework with regard to the provision of Air Traffic Services within the framework of
Commission Implementing Regulation (EU) 2016/1377 on common requirements for ATM/ANS (ATM/ANS Common Requirements Regulation)
within the framework of the ATM/ANS Common Requirements Regulation 2016/1377. The NPA contains, inter alia, amendments to the upcoming
Executive Director Decision issuing Acceptable Means of Compliance (AMC) and Guidance Material (GM) to the ATM/ANS Common Requirements
Regulation. In particular, it contains a proposed AMC addressing missed approach instructions (see AMC21 ATS.TR.210(a)(3) Operation of ATC
service - MISSED APPROACHES INSTRUCTIONS). The EASA Opinion resulting from the regulatory process for RMT.0464 is planned to be published
during the course of 2017.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 23 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
In addition to that, the contribution of the high nose-up pitch trim seen in some of the G/A events would not
be addressed; additional safety benefit can be gained by better demonstrating adequate longitudinal
controllability and authority during G/A.
Unusual pitch-up trim position in other flight phases
The RMG analysed four events (accidents) where the flight crew lost control of the aircraft and did not
recover. A pitch trim at, or close to, full nose-up position was present in all these events. Such pitch trim
position developed when the airspeed of the aircraft decreased as a result of a technical failure on an aircraft
equipment. When the aircraft approaches or reaches the stall speed, this pitch trim configuration, combined
with high thrust application, substantially decreases pitch authority when the pilot attempts to recover from
the upset or the stall. This, therefore, contributes to maintaining the aircraft in an inappropriate position for
the recovery. On some designs, the autopilot can even continue to send pitch-up orders to the autotrim after
the stall warning. The pitch trim position must then be decreased, either manually by the flight crew or by the
autotrim function if available.
It is, therefore, suitable to have a means to stop or limit the pitch trim travel at low speed when approaching
the stall warning. Nevertheless, the analysis of the above mentioned events concluded that the presence of
such means would probably not have changed the final outcome because of other more preponderant
contributing factors (for instance if the flight crew does not apply an adequate stall recovery procedure).
Actions in the area of flight crew training are initiated which can help mitigating these events. RMT.0581 on
‘Loss of Control Prevention and Recovery Training’ is on-going; the new training requirements will include:
— recovery from stall events in clean configuration, at low altitude and near the maximum operating
altitude;
— recovery from nose-high upsets at various bank angles; and
— manual flight with and without flight directors (no autopilot, no autothrust/autothrottle, and at
different control laws, where applicable).
Airbus took action to improve the aircraft design based on the lessons learnt from particular circumstances in
the A320 accident in Canet-plage, being:
— the alert to ‘manual pitch trim’ is now maintained in abnormal attitude law;
— the auto trim function disengagement logic now disengages in normal laws also when the airspeed
drops below a threshold (a value above the stall speed).
In the absence of other regulatory action dealing with design requirements, it is expected that the above
mentioned actions will provide a safety improvement. The RMG did not identify a design requirement which
would have substantially mitigated the four events reviewed. However, an additional safety benefit can be
gained by upgrading certification specifications to ensure that the autotrim function, when installed, will stop
trimming the aircraft when the airspeed approaches the stall warning speed.
Third countries
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 24 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
In the USA, the FAA published SAFO 15004, ‘Scenario-Based Go-Around Training’, in 201514.
4.2. How it could be achieved — options
In order to achieve the objectives mentioned in Chapter 2.2 the following options have been envisaged:
Option 0 does not propose any changes to the current regulatory framework and relies on other action
already launched. Please refer to Chapter 4.1.3.
Option 1 proposes to amend CS-25, applicable to all new large aeroplane designs, in order to:
— Upgrade the assessment of the G/A manoeuvre and its procedure. The goal is to evaluate if a G/A with
AEO can be managed without creating excessive workload on the crew and without an excessive risk of
somatogravic illusion. When an unacceptable level of risk is identified, the applicant has to implement
design solutions to decrease this risk to an acceptable level. Implementing a reduced G/A thrust
function is one of the potential solutions which can be used, as it allows to provide more time to the
flight crew (on some two-engined aeroplanes it can range from 30 s to 1 min, assuming an average
2 000 ft/min rate of climb is maintained), and it decreases the dynamic of the manoeuvre, thus
mitigating the risk of mis-management of the aeroplanes’s trajectory (including the effect of
somatogravic illusion). As other means may be proposed by industry, this is considered as an acceptable
means of compliance (AMC);
— Upgrade the existing specifications and acceptable means of compliance related to longitudinal control
and authority during G/A or other flight phases. For G/A, the aim is to demonstrate adequate
longitudinal controllability and adequate stall margin during transition from any approved approach and
landing configuration to G/A and up to the next flight phase and level-off (AEO and full thrust/power,
different combinations of automatisms to be evaluated). For other flight phases, when the aeroplane
has an automatic pitch trim function, the stabiliser (or trim tab) travel should be limited before or at
stall warning activation to prevent excessive pitch trim such that it is possible to command a prompt
pitch down of the aircraft for control recovery.
Option 2 is made of Option 1 plus a Part-26/CS-2615 regulation to require already certified large aeroplanes
most-at-risk (wing-mounted twin turbofan) to implement design changes to mitigate the risk of excessive work
load and somatogravic illusion during G/A. Similarly as for the new designs (CS-25), an AMC is the
implementation of a reduced G/A thrust function. The scope of applicability is limited to the most-at-risk
aeroplanes consistently with the history of reported occurrences.
Option 3 is Option 2 plus a Part-26/CS-26 regulation to require already certified large aeroplanes most-at-risk
(wing-mounted twin turbofan) to implement design changes to improve the longitudinal controllability and
authority during G/A and other flight phases. Similarly as for the new designs (CS-25), the aim is to
demonstrate adequate longitudinal controllability and stall margin during the G/A, and that, for other flight
phases, pitch trim surfaces travel is limited before or stall warning to prevent excessive pitch trim such that it
14
Safety Alert for Operators 15004 dated 3/10/15, ‘Scenario-Based Go-Around Training’, available under:
https://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo/all_safos/
15
Existing designs can be addressed by amending Commission Regulation (EU) 2015/640 of 23 April 2015 on additional airworthiness specifications
for a given type of operations and amending Regulation (EU) No 965/2012, including its annex I Part-26, which is applicable to aircraft:
(a) registered in a Member State;
(b) registered in a third country and used by an operator for which a Member State ensures oversight.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 25 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
is possible to command a prompt pitch down of the aircraft for control recovery. Like Option 2, the scope of
applicability is limited to the most-at-risk aeroplanes consistently with the history of reported events.
Table 1: Selected policy options
Option Short title Description
No
0 No regulatory change (other than the ones mentioned in 4.1.3).
1 Amend CS-25 :
- to upgrade the evaluation of the G/A manoeuvre (focus on workload
and risk of somatogravic illusion) and mitigate any excessive risk
identified; and
- upgrade the demonstration of adequate longitudinal controllability
and authority during go-around and other flight phases.
2 Option 1 + amend Part-26/CS-26 to require already certified large
aeroplanes most-at-risk (wing-mounted twin turbofan) to implement
design changes to mitigate the risk of excessive work load and
somatogravic illusion during G/A.
3 Option 2 + amend Part-26/CS-26 to require already certified large
aeroplanes most-at-risk (wing-mounted twin turbofan) to implement
design changes to improve the longitudinal controllability and authority
during go-around and other flight phases.
4.3. What are the impacts
4.3.1. Safety impact
If no regulatory action is taken (Option 0) the future level of risk is dependent on the implementation of other
regulatory activities launched, and also on the future evolution of aeroplane designs as decided by the
manufacturers.
Already launched regulatory activities are focusing on G/A safety in the domains of flight crew training and
ATM/ANS rules related to missed approach procedures.
It is believed by the RMG, and also by several other manufacturers not represented in the RMG, that the effort
to improve flight crew G/A training (in particular with regard to conducting G/A with all engines operating) is
the most important action to improve safety, in the short and long term. This is covered by RMT.0581.
However, the design of the aeroplane can provide further safety improvement by ensuring that the G/A
manoeuvre can be handled as smoothly as possible and without excessive performance levels in the
longitudinal direction which can exacerbate the risk of somatogravic illusion or create unnecessary high peaks
of workload for the flight crew. Airbus and Boeing, manufacturers of the majority of the most-at-risk
aeroplanes (as demonstrated by reported accidents and incidents), have already taken action to implement
reduced G/A thrust functions which help improving safety even without a new regulatory action on the design
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 26 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
domain. However, some manufacturers of aeroplanes which have design chracteristics putting them in the
same most-at-risk category have not yet taken action. Therefore, similar G/A accidents or incidents may
happen to these aeroplanes in the future if no action is taken even if the risk would be mitigated by other
existing activities (e.g. RMT.0581).
Furthermore, as highlighted by accidents and incidents involving G/A or other flight phases, there is also a
need to review and upgrade requirements for longitudinal controllability and authority.
Therefore, Option 0 is not optimal from a safety point of view, and a regulatory action in the design area has
to be considered.
Option 1 addresses the points mentioned above for new designs once CS-25 has been amended. This would
ensure that all manufacturers develop new designs with elements that could ensure a safer G/A manoeuvre,
and also an adequate longitudinal controllability and authority when transitioning from low speed phases of
flight (G/A and other fligh phases). Globally, such action could have provided some level of mitigation to 14 out
of the 25 G/A-related occurrences reviewed by the RMG, as detailed below:
— 11 events (5 accidents and 6 incidents or serious incidents) could possibly have been mitigated to a
certain extent by a reduced G/A thrust function,
— 6 events (2 accidents and 4 incidents or serious incidents) could possibly have been mitigated by a
means to limit, or correct, the pitch trim travel at low speed.
Theoretically, an optimal safety improvement would be gained through application of retroactive
requirements to improve the design of existing types of aeroplanes. In this respect, Option 3 could be the best
option.
The analysis on the need of a retroactive regulation performed by the RMG, considering the history of events
to date, concluded that:
a) Go-around manoeuvre management risk mitigation
As of today, the main design means identified to further mitigate the risk of inadequate management of the
G/A manoeuvre on aeroplanes most-at-risk is a reduced G/A thrust system. However, it is also recognised that
the presence of this function cannot always prevent G/A events. For example, there are 4 occurrences that
happened in spite of the presence and selection of a G/A thrust reduction system: B737-500 N904UA in San
Francisco (incident), B737-500 D-AHLN in Bremen (incident), B737-500 VQ-BBN in Kazan (accident), B737-300
EX-37005 in Osh (accident). Somatogravic illusion as contributing factor has been considered as possible in the
case of D-AHLN, and probable in the case of VQ-BBN and EX-37005.
Also, the proposal for amending CS-25 (Option 1) does not mandate a reduced G/A thrust function; this
remains an acceptable means of compliance with a specification requiring to mitigate any excessive risk
identified through a specific evaluation.
Furthermore, training to conduct G/A with AEO remains the priority action in the opinion of the RMG as this
action is the one providing probably the highest and quickest mitigation and safety benefit for the full fleet of
operated large transport aeroplanes. In addition, there are situations where the pilots must apply full thrust
and must be able to safely manage the manoeuvre anyway (e.g. presence of windshear, avoidance
manoeuvre, obstacle clearance).
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 27 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
The vast majority of the reported and analysed events concern Airbus and Boeing aeroplanes.
Airbus has implemented such a function on the most recent types (standard modification on A380 and A350
aircraft which are all equipped). It is now being implemented on the A320 NEO family (certified on A320 end
2016, and to be certified on the A321 in 2017) and the A330 (CEO and NEO); operators, nevertheless, can
chose to select the option or not, for example based on fleet mixability strategy. Only the A300/A310, the
A320 family CEO, and the A340 types will not receive this function because of considerations including
technical feasibility at a reasonable cost, fleet size and usage, out-of-production status, or criticality of the
climb capability.
Looking at accidents involving Airbus aircraft that will not receive a reduced G/A thrust function:
— A300/A310: 2 accidents (in 1994 and 1998) could have been mitigated by such function; however the
mitigation factor is estimated to maximum 30 % by the RMG for each event; therefore the accidents
may not have been avoided;
— A320 CEO family: 2 accidents (in 2000 and 2006) happened, but only 1 (the Bahrain accident) could have
been mitigated by such function. The actual mitigation factor is difficult to estimate given all the other
human factor issues involved in this event. A mitigation factor of 50 % may be proposed; therefore there
is no certainty that the accident could have been avoided.
Boeing implemented a reduced G/A thrust function on a large portion of their fleet which includes all current
production aircraft and others: last couple of hundred 737-200’s; 737-300 through 737-900; 737 MAX; some of
the 747-100 to 747-300; 747-400; 757; 767; 777; 787.
All Boeing aeroplanes involved in the 4 accidents reviewed were equipped with the function. However, the
function was used in only 2 of the accidents (737-500 in Kazan and 737-300 in Osh) for which somatogravic
illusion is considered as a probable factor. In 1 of the other accidents (737-800 in Rostov-on-Don), the function
was not used because of presence of windshear was suspected; somatogravic illusion is a probable factor. In
the last accident (777 in Dubai), the flight crew pushed the TO/GA switch for an automatic G/A after
touchdown; as per design an automatic G/A is not possible after touchdown, the G/A mode was not activated
and, therefore, the reduced G/A could not be used.
The three events not concerning Airbus or Boeing aeroplanes involved a DC-8, a SA226 Metro, and a DHC-8. In
the opinion of the RMG, the presence of a reduced G/A thrust function could have positively influenced only
the SA226 event, although the outcome of the other events would not have been changed because of other
involved factors.
Fokker, has also developed a function which mitigates the risk of the G/A manoeuvre. The function,
implemented on Fokker 70/100 aeroplanes (tail mounted twin turbofan), allows to maintain a safe pitch
attitude and can reduce the thrust in order to limit the rate of climb to a reasonable value while following a
target airspeed.
Finally, a review of the registration numbers of the aeroplanes involved in the accidents (list of events
identified in this RMT), where a possible mitigation by a reduced G/A thrust function is identified by the RMG,
shows that all these (five) aeroplanes were registered in third countries and not under the oversight by a
Member State. Therefore, they would not fall under the scope of applicability of Commission Regulation (EU)
2015/640 (Part-26).
For all these reasons, the additional safety benefit which could be brought from a retroactive mandate for a
G/A risk mitigation means like the reduced G/A thrust function is considered very limited.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 28 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
b) Longitudinal controllability and authority
The review of G/A related events indicates that:
— 6 events (2 accidents, 4 incidents) involved a pitch trim at, or close to, full nose‐up position. Assuming
the implementation of a system able to limit the travel of the pitch trim to a safe value before G/A
initiation (keeping enough pitch down authority), 1 accident receives a very low estimated potential
mitigation, the other accident a moderate estimated potential mitigation. For the incidents, the
potential mitigation weight estimation ranges from low to moderate. In all cases, the pitch trim position
is considered as a contributor, but any improvement action taken to avoid this position being selected
or maintained would not guaranty that the final outcome of the event would be changed;
— The aeroplane types involved in the above events (6 A300/A310, 1 B737-300) are old ones which will be
progressivelly retired from service. Nevertheless, design improvements have been brought to some
models when possible.
— Costs and complexity involved in the investigation and modification of the aircraft pitch controllability,
its auto trim function, or its alerting system are deemed to be very high and must be balanced by a
strong safety case, which is not apparent in the opinion of the RMG.
For events in other flight phases:
— 4 accidents were reviewed where the nose-up pitch trim position contributed to the event because the
flight crew did not take action to trim the aircraft;
— The estimated potential mitigation from the implementation of a system able to limit the travel of the
pitch trim to a safe value is very low for 3 events, and higher for 1 event. However, this last event (A320
D-AXLA) was a very particular failure case (AoA probes were frozen because of inappropriate
maintenance action) after which the aircraft flight control law was not anymore in the normal law
configuration (switch to direct law and then abnormal attitude law). The manufacturer (Airbus) has
implemented design changes mitigating the risk of such scenario (the PFD alert to manually pitch trim is
now maintained in abnormal attitude law. The auto trim function disengagement logic has been
improved, it now disengages also when the airspeed drops below a threshold (a value above the stall
speed)).
The estimated safety benefit from an improvement of the pitch trim position control in these events is,
therefore, very limited. Pilot training improvements to upgrade the pilots’ knowledge of the different flight
control laws (refer to RMT.0581 on UPRT) are considered more beneficial in terms of safety improvement.
Summary of safety impact:
Option 0 would rely on other activities to improve safety. If this option is selected, it is expected that safety of
G/A manoeuvres will improve in the coming years due to the outcome of other regulatory activities (flight
crew G/A training, missed approach instructions improvements), and the increase of the number of aeroplanes
equipped with a reduced G/A thrust function (mainly driven by the Airbus fleet evolution). This option would
not address improvements which can be made in the area of longitudinal controllability and authority.
Option 1 would allow to consolidate in CS-25 the actions already launched by Airbus, Boeing, and Fokker. This
would ensure a safety improvement for all new designs from all manufacturers.
Option 2 would add a safety benefit for Airbus and Boeing aircraft that are not yet equipped with a reduced
G/A thrust function. This would also require other manufacturers of aeroplanes of similar risk (wing mounted
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 29 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
twin turbofan) to implement a mitigation means for G/A, if this has not already been done. However, no event
has been reported to date on these aeroplanes. Overall, the additional safety benefit from Option 2, compared
to Option 1, is considered low.
Option 3 would bring a very low additional benefit compared to Option 2.
4.3.2. Environmental impact
All options do not have significant environmental impacts.
4.3.3. Social impact
All options do not have significant social impacts.
4.3.4. Economic impact
Cost impacts is assessed mostly qualitatively in this chapter because of 1) the very limited information
received by the RMG, and 2) the lack of replies to quantitative questions in the questionnaire sent to
manufacturers.
Description of costs impacts falls in the following categories:
Non-recurring costs (NRC) (average cost impact per aeroplane manufacturer/type certificate holder):
— ‘very high’ impact: overall cost impact of 300 million euros or more;
— ‘high’ impact: overall cost impact between 150 and 300 million euros;
— ‘medium’ impact: overall cost impact between 50 and 150 million euros;
— ‘low’ impact: overall cost impact between 15 and 50 million euros;
— ‘very low’ impact: overall cost impact between 5 and 15 million euros;
— ‘negligible’ impact: overall cost impact up to 5 million euros.
Recurring costs (RC) (average cost impact per operator/owner of aeroplanes):
— ‘very high’ impact: overall cost impact of 30 million euros or more;
— ‘high’ impact: overall cost impact between 15 and 30 million euros;
— ‘medium’ impact: overall cost impact between 5 and 15 million euros;
— ‘low’ impact: overall cost impact between 1,5 and 5 million euros;
— ‘very low’ impact: overall cost impact between 0,5 and 1,5 million euros;
— ‘negligible’ impact: overall cost impact up to 0,5 million euros.
Option 0 is the reference option and does not create significant impacts.
Option 1: For new CS-25 aeroplane designs, the following costs are assessed:
— Non-recurring costs (NRC):
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 30 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
For manufacturers, investigation of the management of the G/A manoeuvre, and eventually the
development and certification of mitigation means, which could include a reduced G/A thrust
function (acceptable means of compliance). In case such function would have to be developed,
the NRC is estimated by the RMG to be several tenths of millions euros (50 million euros can be
taken as an order of magnitude), therefore, overall the NRC would be ‘medium’ (ranging from
‘very high’ for small manufacturers to ‘low’ for large manufacturers). However, when included in
the development of a new design type, this cost is considered as not substantial and acceptable
for a CS-25 large aeroplane manufacturer.
Upgrade of the development and certification of means to ensure adequate longitudinal
controllability and authority during go-around and other flight phases. This may entail some new
design specifications (if not already implemented by the manufacturer) to the pitch attitude
control system and/or the (automatic) pitch trim system. The cost impact could range from ‘low’
to ‘medium’. When embedded inside the development of a new aeroplane design, this NRC is also
negligible for a CS-25 large aeroplane manufacturer.
— Recurring costs (RC):
The implementation of a risk mitigation means for the G/A manoeuvre, and by the eventual new
specifications on the pitch attitude control system and/or the (automatic) pitch trim system,
would have potential hardware and software impacts. As these impacts would be integrated
within the development of a new CS-25 type, they would have a ‘negligible’ effect on RC to be
supported by operators/owners of aeroplanes. Often, software changes are the main impact.
Maintenance or operational RC are deemed to be ‘zero’ or ‘negligible’.
For pilot training, if a reduced G/A thrust function is implemented, there will be a need for a
specific theoritical and practical training to use it; the associated cost is considered ‘negligible’
compared to the overall costs of pilot type rating and recurrent traning programmes which
already include various elements for the G/A manoeuvre (re-inforced by new requirements from
RMT.0581).
Option 1 would create medium NRC for manufacturers when developing a new design type, but is considered
acceptable. For some of them, they have anyway already developed a reduced G/A thrust function on some
existing aeroplanes and would mainly have to work on longitudinal controllability and authority aspects. RC for
operators/owners of aeroplanes are ‘negligible’.
Option 2: This option includes the costs assessed for Option 1 plus the costs which are applicable to already
certified large aeroplanes most-at-risk (wing-mounted twin turbofan) to implement design changes to mitigate
the risk of excessive work load and somatogravic illusion during G/A. A reduced G/A thrust function would be
one acceptable means of compliance. The aeroplanes impacted are the ones within the scope of Commission
Regulation (EU) 2015/640, i.e.:
(a) registered in a Member State;
(b) registered in a third country and used by an operator for which a Member State ensures the oversight.
— Non-recurring costs (NRC):
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 31 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
Development and certification of mitigation means, which could include a reduced G/A thrust
function. In case such function would have to be developed, the NRC is estimated by the RMG to
be several tenths of millions euros (50 millions euros can be taken as an order of magnitude). This
is considered as a ‘medium’ NRC for already certified aeroplanes. The technical feasibility of a
reduced G/A thrust function may be challenging for the older designs that are out of production
but still in service, and the NRC for these types would be higher than for modern types where
implementation can be done by software updates as opposed to more complex hardware
changes.
Airbus and Boeing already developed a compliant function but for a part of their fleets only, after considering
different factors such as: technical feasibility at a reasonable cost, fleet size and usage, out-of-production
status, or criticality of the climb capability. If full retrofit is selected, they would have to develop a function on
the older types in service and within the scope of applicability of Commission Regulation 2015/640.
— Recurring costs (RC):
Costs created by the implementation of a risk mitigation means for the G/A manoeuvre, e.g.
reduced G/A thrust function. On a modern aeroplane, such mitigation means would probably
create ‘negligible’ or none-hardware RC, but would rather essentially be managed by software for
which RC impact is ‘null’. Older types would face higher RC from needed hardware changes;
nevertheless, such cost should be moderate and would probably fall in the ‘low’ or ‘negligible’
category for aeroplane unitary cost impact to be supported by operators/owners.
No new maintenance or operational costs are anticipated for modern aeroplanes. For older
designs, additional maintenance costs could be created, however, such costs would be
‘negligible’.
For pilot training, if a reduced G/A thrust function is implemented, there will be a need for a
specific theoritical and practical training to use it. The associated cost is considered very low
compared to a global pilot traning programme which already includes various elements for the
G/A manoeuvre (re-inforced by new requirements from RMT.0581). Furthermore, the largest part
of the fleet (Airbus and Boeing) is equipped anyway, independently of the new CS-25
specifications, and, therefore, training requirements are in place for the corresponding pilots.
Overall this RC impact is ‘negligible’.
In addition to Option 1 costs, Option 2 would create ‘medium’ NRC for manufacturers (‘very high’ for small
manufacturers and ‘low’ to ‘medium’ for large ones) for their affected already certified aeroplanes.
Furthermore the technical complexity of needed changes may be high on older types of aeroplanes, thus
eventually economically not acceptable for the oldest and smallest fleets. ‘Negligible’ RC (or ‘low’ RC for older
types) are expected for operators/owners.
Option 3: This option includes the costs assessed for Option 2 plus the costs applicable to already certified
large aeroplanes most-at-risk (wing-mounted twin turbofan) to implement design changes to improve the
longitudinal controllability and authority during go-around and other flight phases. The aeroplanes impacted
are the ones within the scope of Commission Regulation (EU) 2015/640, i.e.:
(a) registered in a Member State;
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 32 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
(b) registered in a third country and used by an operator for which a Member State ensures oversight.
— Non-recurring costs (NRC):
Development and certification of means to investigate and improve the longitudinal
controllability and authority during go-around and other flight phases for already certified
aeroplanes. This activity may lead to a need to modify the pitch attitude control system and/or
the (automatic) pitch trim system. This is considered as ‘medium’ NRC, potentially significant for
the older types that are not produced anymore.
— Recurring costs (RC):
Costs created by the implementation of the modification(s) to improve the longitudinal
controllability and authority. This can imply light to heavy hardware changes, depending on the
systems and items that are affected. Software changes would probably also be associated to
harware changes. Overall these RC could be ‘negligible’ to ‘low’ for aeroplane unitary cost impact
to be supported by operators/owners.
There are potential additional maintenance and operational costs associated to the hardware
changes on pitch trim control system and/or (automatic) pitch trim system. However, such costs
are deemed to be ‘negligible’.
For pilot training, there could be a need to update the knowledge on the modified system(s) and
operational procedure(s) if changed. This is considered as ‘negligible’ impact.
In addition to the impacts highlighted in Option 2, Option 3 would create further ‘medium’ NRC for
manufacturers (siginificant for older types of aeroplanes). ‘Negiligible’ to ‘low’ RC would be created for
operators/owners.
Question to stakeholders on impacts:
Stakeholders are invited to provide any other quantitative information they may find necessary to bring
to the attention of EASA.
As a result, the relevant parts of the RIA might be adjusted on a case-by-case basis.
4.4. Conclusion
4.4.1. Comparison of options
Option 0 is taken as reference for the comparison of other options, and is therefore considered neutral in the
table below.
Option 0 Option 1 Option 2 Option 3
(Reference option)
Safety impact 0 ++ ++ ++
Environmental 0 0 0 0
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 33 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
impact
Social impact 0 0 0 0
Economic impact 0 - -- ---
NRC: ‘medium’ NRC: ‘medium’ + high NRC: ‘high’ + high
RC: ‘negligible’ complexity for older complexity for older
types types.
RC: ‘negligible’ to RC: ‘negligible’ to
‘low’ ‘low’
Overall safety benefit 0 + 0 -
vs. cost
The selection of the best option consists in a comparison between the potential safety benefit against the
associated costs for impacted stakeholders.
Option 0 is neutral. Selecting this option would mean to rely on other launched activities to improve safety
(pilot training, missed approach instructions).
Option 1 would provide a fair safety benefit by requiring that all new CS-25 aeroplanes have design features
which ensure that managing a G/A manoeuvre does not create an unacceptable risk of loss of control of the
trajectory or loss of control of the aeroplane, including the risk of somatogravic illusion. Airbus, Boeing and
Fokker already developed systems to reduce the thrust during G/A. These systems avoid applying excessive
thrust and thereby providing more time to the flight crew to perform required activities, and they reduce the
dynamic of the flight phase which decreases the risk of somatogravic illusion. Such design improvement effort
would be required from other manufacturers developing aeroplanes that can also present a similar level of
risk. In addition, Option 1 would require manufacturers to investigate further the longitudinal controllability
and authority in G/A and other flight phases, which would contribute to mitigate the risk of upset attitudes
and loss of control, in particular in relation with the effect of the automatic pitch trim. The NRC cost impact of
this option is ‘medium’ for manufacturers that have not yet developed a mitigation means like a reduced G/A
thrust function, however, when included in the development of an aeroplane, this is not significant relative to
the overall cost of a development. Operators/owners would not face, or only negligible, RC associated to these
design improvements.
Option 2 would, in addition to Option 1, mandate manufacturers that have not yet launched activities to make
a risk assessment and eventually develop G/A mitigation means, like a reduced G/A thrust function, on already
certified aeroplanes most-at-risk. This could address a pending risk for aeroplanes that have not yet faced
reported events, and would also extend the effort to older Airbus and Boeing aeroplanes that have not been
modified. For recent types the NRC is ‘medium’, but the RC is ‘negligible’ to ‘low’ (design changes most
probably managed by software updates). For older types, such design changes can be very complex and
generate higher NRC for manufacturers. For some small fleets of out of production aeroplanes this may even
not be economically sustainable. RC would be also higher because of required hardware changes. Overall, it is
believed that the supplementary safety benefit to be gained with Option 2 would not be high enough to
balance the economic burden created for manufacturers and operators/owners.
Option 3 would, in addition to Option 2, mandate an evaluation of already certified aeroplanes most-at-risk to
improve the longitudinal controllability and authority during G/A and other flight phases. Considering that
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 34 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
4. Impact assessment (IA)
Option 2 is not deemed acceptable, and the very low additional safety benefit, Option 3 can be considered as
not acceptable. This conclusion is reinforced by the additional costs created by this option.
Therefore, Option 1 is the recommended option.
4.5. Monitoring and evaluation
As this NPA proposes changes to CS-25 that will apply to new aeroplane type designs, the monitoring of the
effects created by the new specifications and acceptable means of compliance will consist of:
1) feedback from future CS-25 type certification projects, in particular the results of the G/A manoeuvre
risk assessments and longitudinal controllability/authority assessments, and
2) in the long term, trend of accidents and incidents during or after G/A (i.e. loss of flight path or loss of
control), or in other flight phases at low speed (where longitudinal controllability or authority is a
factor).
Item 1 depends on the applications received after amendment of CS-25. A review could not be made earlier
than 5 years after CS-25 amendment.
Item 2 would be available once the new type designs have entered into service and experienced sufficient
flight time, which would require several years (at least 5 years to get relevant statistical information).
In addition, the changes made to CS-25 might be subject to interim/on-going/ex-post evaluation that will show
what is the outcome obtained after application of the new rules, taking account of earlier predictions made in
this impact assessment. The evaluation will provide an evidence-based judgement of the extent to which the
proposal has been, relevant given the needs and its objectives, effective and efficient, coherent, and has
achieved EU added-value. The decision whether an evaluation will be necessary will be taken based also on the
monitoring results.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 35 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
5. Proposed action to support implementation
5. Proposed action to support implementation
— Focused communication for advisory body meeting(s) (TeB, STeB)
(Advisory body members)
N/A
— Providing supporting clarifications in electronic communication tools EASA - NAAs (CIRCABC,
SINAPSE or equivalent)
(Primarily targeted audience Competent Authority)
N/A
— EASA Circular
(Primarily targeted audience Competent Authority, Industry)
N/A
— Detailed explanation with clarification and indicated hints on the EASA web
(Industry, Competent Authority)
N/A
— Dedicated thematic workshop/session
(Industry, Competent Authority)
N/A
— Series of thematic events organised on the regional principle
(Industry, Competent Authority)
N/A
— Combination of the above selected means
(Industry, Competent Authority)
N/A
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 36 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
6. References
6. References
6.1. Affected/Related regulations
— None.
6.2. Affected decisions
— ED Decision 2003/002/RM (CS-25).
6.3. Other reference documents
Study on Aeroplane State Awareness during Go-Around (ASAGA), published in August 2013. The report
is available on the Bureau d’Enquêtes et d’Analyses pour la sécurité de l’aviation civile (BEA) website at :
https://www.bea.aero/en/safety-studies/access-to-studies/aeroplane-state-awareness-during-go-
around/
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 37 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
7. Appendices
Appendix 1: List of occurrences analysed by the RMG
Category 1 occurrences:
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A310 (turbofan) 11/02/1991 Moscow Incident None 0 ON REQUEST OF ATC THE PILOT INITIATED
- D-AOAC (Russia) GO-AROUND AT 1,400 FT. THE CREW FELT
(Germany) THAT THE A/C PITCH ATTITUDE
INCREASED ABNORMALLY AND TRIED TO
OVERRIDE THE NOSE-UP TENDENCY BY
MOVING THE CONTROL COLUMN
FORWARD. THIS CAUSED AUTOPILOT
NO.1 TO DISENGAGE.
DISENGAGEMENT OF THE AUTOPILOT
DISABLED THE AUTOTRIM AND THE
STABILIZER REMAINED IN THE FULL NOSE-
UP POSITION WHILE THE CONTROL
COLUMN WAS MOVED FORWARD. THE
A/C PITCHED-UP AND SPEED WAS
REDUCED. AT 4,000 FT THE A/C STALLED
THEN CLIMBED AND STALLED AGAIN AT
5,700 FT. AT 11,755 FT, AFTER TWO
ADDITIONAL STALLS CONTROL WAS
REGAINED BY REDUCING THRUST AND
MANUAL TRIM.
THE A/C LANDED SAFELY USING MANUAL
CONTROL. LACK OF CREW CO-
ORDINATION AND COCKPIT RESOURCE
MANAGEMENT CONTRIBUTED TO THE
EVENT.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 38 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A300-600 26/04/1994 Nagoya Accident Destroyed 264 While the aircraft was making an ILS
(turbofan) - B- (Japan) approach to runway 34 of Nagoya Airport,
1816 (China) under manual control by the F/O, the F/O
inadvertently activated the GO lever,
which changed the FD (Flight Director) to
GO AROUND mode and caused a thrust
increase. This made the aircraft deviate
above its normal glide path. The APs were
subsequently engaged, with GO AROUND
mode still engaged. Under these
conditions the F/O continued pushing the
control wheel in accordance with the
CAP's instructions. As a result of this, the
THS (Horizontal Stabilizer) moved to its
full nose-up position and caused an
abnormal out-of-trim situation. The crew
continued approach, unaware of the
abnormal situation. The AOA increased
the Alpha Floor function was activated
and the pitch angle increased.
It is considered that, at this time, the CAP
(who had now taken the controls), judged
that landing would be difficult and opted
for go-around. The aircraft began to climb
steeply with a high pitch angle attitude.
The CAP and the F/O did not carry out an
effective recovery operation, and the
aircraft stalled and crashed.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 39 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A310 (turbofan) 24/09/1994 Paris Orly Incident None 0 The direct causes of the unusual attitudes
- YR-LCA (France) and the stall to which the aircraft was
(Romania) subjected were a movement of the THS
towards the full pitch-up position and a
rapid increase in thrust, both of which
maneuvers were the due to the Captain,
following an AFS mode reversion which
was not understood. The pitch-up force
caused a sudden change in attitude that
the flight crew was unable to contain with
the elevators.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 40 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A310 (turbofan) 11/12/1998 Surrathani Accident Destroyed 101 The accident occurred because the aircraft
- HS-TIA (Thaïland) entered into stall condition which might
(Thailand) have been caused by the followings:
1. The pilot attempted to approach the
airport in lower than minimum visibility
with rain.
2. The pilot could not maintain the VOR
course as set forth in the approach chart.
The aircraft flew left of VOR course on
every approach.
3. The pilots suffered from the
accumulation of stress and were not
aware of the situation until the aircraft
emerged into the upset condition.
4. The pilots had not been informed of the
document concerning the wide-body
airplane upset recovery provided by
Airbus Industrie for using in pilot training.
5. The lighting system and approach chart
did not facilitate the low visibility
approach.
6. Stall warning and pitch trim systems
might not fully function as described in
the FCOM and AMM.
A310 (turbofan) 27/06/2000 Dubai Incident None 0 AT 500 FT AGL ON FINAL APP TO DUBAI
- A6-EKG (United A/P, THE TRIMMABLE HORIZONTAL
(United Arab Arab STABILISER (THS) TRIM MOVED TO
Emirates) Emirates) MAXIMUM DEFLECTION NOSE UP. THE
A/C WAS BEING FLOWN MANUALLY BY
THE FIRST OFFICER. SHORTLY
AFTERWARDS A GO-AROUND WAS MADE
DUE TO BEING HIGH AND FAST ON APP.
DURING THE GO-AROUND, THE A/C
PITCHED UP TO 46 DEG PITCH AND
STALLED, DESPITE FULL FORWARD NOSE
DOWN ELEVATOR.
RECOVERY ACTION WAS MADE BY
REDUCING THRUST TO IDLE. THE LOW
SPEED PROTECTION SYSTEM OPERATED
NORMALLY BUT THE INCREASE
IN THRUST RESULTED IN A FURTHER HIGH
NOSE ATTITUDE AND STALL FROM WHICH
THE CAPTAIN RECOVERED USING SAME
RECOVERY ACTION.
NO TECHNICAL REASON FOR THE THS
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 41 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
MOVEMENT HAS BEEN FOUND.
A320 (turbofan) 23/08/2000 Bahrain Accident Destroyed 143 The individual factors during the approach
- A4O-EK and final phases of the flight were:
(Oman) -non-adherence to standard operating
procedures (SOPs) by the captain;
-the first officer not drawing the attention
of the captain to the deviations of the
aircraft from the standard flight
parameters and profile;
-the spatial disorientation and information
overload experienced by the flight crew;
-and, the non-effective response by the
flight crew to the ground proximity
warnings.
The systemic factors that could have led
to these individual factors were: a lack of
a crew resources management (CRM)
training programme; inadequacy in some
of the airline’s A320 flight crew training
programmes; problems in the airline’s
flight data analysis system and flight
safety department which were not
functioning satisfactorily; organisational
and management issues within the airline;
and safety oversight factors by the
regulator.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 42 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A320 (turbofan) 03/05/2006 Black sea Accident Destroyed 113 The fatal crash of the “Armavia” A-320 EK-
- EK-32009 (Russia) 32009 was a CFIT accident that happened
(Armenia) due to collision with the water while
carrying-out a climbing manoeuvre after
an aborted approach to Sochi airport at
night with weather conditions below the
established minima for runway 06.
While performing the climb with the
autopilot disengaged, the Captain, being
in a psychoemotional stress condition,
made nose down control inputs due to the
loss of pitch and roll awareness. This
started the abnormal situation.
Subsequently the Captain's inputs in the
pitch channel were insufficient to prevent
development of the abnormal situation
into the catastrophic one.
Along with the inadequate control inputs
of the Captain, the contributing factors to
development of the abnormal situation
into the catastrophic one were also the
lack of necessary monitoring of the
aircraft descent parameters (pitch
attitude, altitude, vertical speed) by the
co-pilot and the absence of proper
reaction by the crew to the EGPWS
warning.
A330-200 30/03/2007 Abidjan Serious None 0 During the final approach, the flight crew
(turbofan) - F- (Ivory incident faces a significant tail wind. At around
GZCC (France) Coast) 100ft, the tail wind increases beyond 10
kts. The Captain, PF, decided to abort the
approach. The G/A altitude is quickly
reached, the PF uses the elevator to
decrease the pitch and reduces the thrust.
The speed increases rapidly and the
indication LVR CLB flashes on the FMA.
Meanwhile, additional pitch down actions
are recorded and the pitch decreases to
negative values. The vertical speed
reaches -4000ft/min. The PF reacts with a
pitch up action, the PNF intervenes too.
Sink Rate and Pull Up alarms are triggered
by the GPWS. The rest of the flight and
landing happen normally.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 43 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A320 (turbofan) 21/07/2007 Melbourne Serious None 0 During an approach to Melbourne Airport,
- VH-VQT (Australia) incident Victoria in instrument meteorological
(Australia) conditions, the flight crew did not have
the required visual reference at the
missed approach point and commenced a
missed approach (go-around). The pilot in
command (PIC) did not move the thrust
levers to the correct position to allow the
aircraft flight mode to correctly transition
to the go-around phase. That led to crew
confusion, which was compounded by
alerts and warnings that distracted them;
the end result was a higher-than-normal
and unexpected workload, and the crew
being unaware of the aircraft’s current
flight mode. The aircraft was not in the
correct flight mode for a period of 48
seconds and during that time, reached a
minimum recorded height of 38 ft above
the runway. Subsequently, the PIC moved
the thrust levers to the correct position,
the flight mode transitioned to the go-
around phase and the aircraft responded
normally.
A319 (turbofan) 23/09/2009 Paris CDG Serious None 0 During go around initiation, the PF did not
- F-GRHU (France) incident set the throttle to the TOGA position, the
(France) rest of actions though being performed
consistently with the procedure. The AP
engagement has been performed without
checking the adequacy of the selected
modes and the FMA displays. During this
dynamic phase, the flight crew
momentarily lost the control of the
trajectory. The attitude was not
monitored.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 44 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A300 B4 13/04/2010 Monterrey Accident Destroyed 6 During the descent, the aircraft was
(turbofan) - XA- (Mexico) configured late for landing.
TUE (Mexico) Then, the final checklist was performed
below 1000ft AGL interrupted several
times by the search of the runway. ATS
being disengaged and engine on idle, the
speed decreased during around 30
seconds from 134kt down to around 110kt
without crew reaction.
Actions to level off the aircraft at MDA by
pulling on the control column between
resulted in speed further decay while
aircraft was pitching up. The low energy
alpha floor protection activated,
advancing the engine throttles and was
continued by crew action on throttles up
to the forward limit. Stick shaker and stall
warning triggered at 04:15:24.
The CPT reacted to the stick shaker and
stall warning activation by quickly
advancing throttles until forward limit (55°
TLA) and announced Go-around. AP was
disengaged.
The control column was pushed forward
to counteract the resulting pitching up
moment. An abnormal force of
approximately 8kg was applied on the
control column during 30 seconds while
no action on the trim setting was
performed. Between 04:15:54 and
04:16:35:
- The aircraft started to climb from 1750ft
to 3800ft while pitching up from an initial
pitch attitude of 5° to reach 41°
- The speed initially increased up to 140kt
(04:16:10) and then decreased to reach a
minimum value below 70kt at 04:16:35.
- Control column was maintained full
forward from 04:16:00 to 04:16:35
- At 04:16:27, stick shaker followed by
stall warning triggered.
- The aircraft stalled
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 45 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
A330-200 12/05/2010 Tripoli Accident Destroyed 103 Based on elements from the investigation,
(turbofan) - 5A- (Libya) the accident resulted from:
ONG (Libya) - The lack of common action plan during
the approach and a final approach
continued below the MDA, without
ground visual reference acquired.
- The inappropriate application of flight
control inputs during a go- around and on
the activation of TAWS warnings,
- The lack of monitoring and controlling of
the flight path.
These events can be explained by the
following factors:
- Limited CRM on approach that degraded
during the missed approach. This
degradation was probably amplified by
numerous radio-communications during
the final approach and the crew’s state of
fatigue,
- Aircraft control inputs typical in the
occurrence of somatogravic perceptual
illusions,
- Inappropriate systematic analysis of
flight data and feedback mechanism
within the AFRIQIYAH Airways.
- Non adherence to the company
operation manual, SOP and standard
terminology.
In addition, the investigation committee
found the following as contributing factors
to the accident:
- Weather available to the crew did not
reflect the actual weather situation in the
final approach segment at Tripoli
International Airport.
- In adequacy of training received by the
crew.
- Occupancy of tower frequency by both
air and ground movements control.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 46 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
B737-500 29/10/1995 San Incident None 0 FOLLOWING A TEST FLIGHT THE PILOT
(turbofan) - Francisco WAS GIVEN A GO-AROUND BY APP
N904UA (USA) (USA) CONTROL. HE SELECTED THE TAKE-OFF
AND GO-AROUND SWITCH AND ENGINE
POWER INCREASED. THE A/C BEGAN TO
PITCH UP AND DID NOT STOP AT THE GO-
AROUND ATTITUDE. PITCH INCREASED TO
45 DEG NOSEUP AND THE STICK SHAKER
ACTIVATED. THE PILOT COULD NOT
OVERCOME THE INCREASE IN PITCH. THE
A/C STALLED, THE NOSE DROPPED AND
THE A/C ROLLED. THE PILOT INCREASED
THE ROLL. AS THE NOSE DROPPED
THROUGH THE HORIZON AIRSPEED
INCREASED AND THE PILOT RECOVERED
TO WINGS-LEVEL.
B737-500 27/04/1998 Bremen Incident None 0 DURING FINAL APP AN UNSAFE NOSE
(turbofan) - D- (Germany) GEAR INDICATION LED TO A GO-AROUND.
AHLN DURING CLIMB-OUT BOTH FLIGHT
(Germany) DIRECTORS AND AUTOTHRUST WERE ON.
AFTER GEAR RETRACTION FLAPS WERE
SET AT 15 DEG. A FURTHER FLAP
RETRACTION WAS DELAYED BY
DISCUSSIONS WITH GROUND CONTROL
REGARDING CHANGING THE DEPARTURE
PROCEDURE BECAUSE OF THE WEATHER.
HIGH THRUST AND LOW A/C WEIGHT
RESULTED IN A CLIMB RATE UP TO 4,800
FT/MIN. THE ALTITUDE CAPTURE FOR A
3,000 FT LEVEL OFF WAS AT 1,500 FT AGL
WHEN THE TOGA MODE SWITCHED TO
MCP SPEED MODE. PITCH ATTITUDE HAD
NOW INCREASED TO 24 DEG NOSE UP.
THEREAFTER, THE FLIGHT DIRECTOR PITCH
BAR COMMANDED A NOSE DOWN,
WHICH THE PILOT FOLLOWED BY
MANUAL NOSE DOWN TRIM INPUT. THIS
LASTED 4 SEC DUE TO THE SLOW
REACTION OF THE A/C.
THE PILOT WAS NOT AWARE THAT WITH
FLAPS AT 15 DEG, THE HORIZONTAL
STABILIZER MANUAL TRIM SPEED
OPERATES AT A MAXIMUM VALUE OF 0.6
DEG/SEC. THE STABILIZER RAN INTO FULL
NOSE DOWN TRIM. THE PITCH ATTITUDE
WAS PASSING 10 DEG NOSE-UP WHEN
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 47 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
FDR SHOWED A SHORT-TIME NOSE-
DOWN ELEVATOR DEFLECTION AND A
REDUCTION OF THRUST LEVER ANGLE.
THE PILOT SAID THAT HE THEN
DISENGAGED THE AUTOTHRUST BUT
THERE WAS NO SUCH INDICATION FROM
THE FDR. WHEN THE PILOT NOTICED THE
NOSE DOWN TRIM HE PULLED THE
CONTROL WHEEL VERY HARD AND
RETAINED FULL CONTROL AFTER SOME
SECONDS. THE FOLLOWING WERE
RECORDED: PITCH ALTITUDE -24 DEG,
ANGLE OF ATTACK -12 DEG, VERTICAL G -
0.4. AFTER FIXING THE UNSAFE GEAR
INDICATION BY CHANGING TWO BULBS
THE A/C LANDED SAFELY.
B757-200 21/01/2002 Gardermo Serious None 0 ILS approach was initially conducted by
(turbofan) - TF- en incident autopilot, but as the A/C never became
FIO (Iceland) (Norway) properly stabilized on GP, the autopilot
was disconnected. The commander flew
the A/C manually, and complained about
his GP data frequently missing. The F/O
did not take any actions to this. His
instruments were functioning normally. At
580 ft, approach was still not stabilized
(above GP), and PIC initiated missed
approach. Pitch was increased to 20 deg.,
and speed decreasing to its peak of 137 kt.
To avoid stalling the A/C the PIC lowered
the nose abruptly, to gain more speed.
The control column was returned to
neutral for a short moment. Then another
abrupt nose-down control movement was
made, causing a pitch attitude to -49 deg.
This dive was not recovered until 321 ft
AGL and 251 kt airspeed. During this
incidence, aural warnings had been
present, like "terrain" and "too low
terrain". The recovery of the dive
continued with a pitch attitude of approx.
+40 deg., and the flight continued
normally, but with several abrupt control
inputs. Load factors during these
abnormal maneuvers were measured to
be -0.6 and +3,59 g's. The A/C made a
normal landing on the 2. attempt.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 48 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
The mass and balance of the aircraft were
within the normal operating limits at the
time of the incident.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 49 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
B737-3Q8 23/09/2007 Bournemo Serious None 0 The co-pilot was PF and the Captain was
(turbofan) - G- uth airport incident PM. During an ILS approach to their base,
THOF (United (United the autothrottle (AT) disconnected
Kingdom) Kingdom) without being noticed by the flight crew
just after the aircraft had captured the
G/S. The thrust was at idle. The autopilot
adjusted the pitch and gradually increased
the nose-up pitch to minimise G/S
deviation as the airspeed decayed. After
selecting flaps 40, the Captain realised
that the aircraft’s IAS was 125 kt (Vref-10
kt). The altitude was then about 1,500 ft.
The Captain took over the controls and
initiated a go-around. About 2 seconds
later the stick-shaker (stall warning)
activated. The Captain moved the thrust
levers fully forward and pushed forward
the control column. The AP mode changed
to CWS. The pitch attitude stabilised at 5°
noseup. The minimum airspeed at this
time was 101 kt. The engine thrust
continued to increase, the AP disengaged,
the pitch attitude started to increase
again and the stick-shaker activated again.
Despite the Captain’s nose-down input,
the nose-up pitch increased to 22°. The
stall warning ceased, but activated again a
few seconds later, just as the flaps were
retracting, and the pitch attitude
increased again, through 27° nose-up. The
co-pilot called out “High Pitch”. The
Captain replied “I have full forward stick”.
The pitch attitude increased above 36°
nose-up, with a CAS of 107 kt, and the
aircraft was in a left roll (~13°). A sharp
rudder input brought the wings level, but
the aircraft was stalled with a peak pitch
attitude of 44° nose-up. The pitch attitude
started to decrease, and the airspeed
continued to decrease for a few seconds,
reaching a minimum of 82 kt when the
pitch attitude was 33° nose-up. After
reaching 2,500 ft, the aeroplane started to
lose altitude. The Captain reduced the
thrust slightly and managed to regain
control of the aircraft at about 2,000 ft. It
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 50 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
was at this point that the flight crew made
the first manual nose-down trim input.
The crew performed a second approach,
during which the AP and the AT operated
nominally.
B757-200 13/12/2008 London Serious None 0 During an approach, in demanding
(turbofan) - G- Gatwick incident weather conditions, the crew
MONK (United (United inadvertently left the speedbrakes
Kingdom) Kingdom) deployed with the auto-throttle
disengaged; the aircraft’s speed decayed
until the stick shaker activated. The Quick
Reference Handbook (QRH) actions for
stick shaker activation were not
completed properly and during the go-
around the speedbrakes remained
extended. Subsequently, the Flight
Director Pitch Bars disappeared from the
Primary Flying Displays (PFDs) and the
commander became disorientated. He
handed over control to the co-pilot and
stowed the speedbrakes realising that
they were still deployed. The crew
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 51 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
subsequently completed an uneventful ILS
and landed safely.
B777 (turbofan) 16/11/2011 Paris CDG Serious None 0 This serious incident was due to the
- F-GSPP (France) incident inadequate monitoring of flight
(France) parameters by the flight crew.
The following factors contributed to this:
- Partial execution of the go-around
procedure;
- Inadequate management of the
automatic systems during execution;
- The conflict of plans of action between
respecting the operators instruction and
continuing the landing, which seemed to
be safely possible according to the
manufacturer.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 52 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
B737-53A 17/11/2013 Kazan Accident Destroyed 50 Performing go-around flight maneuver the
(turbofan) - VQ- airport crew didn't identify the autopilot
BBN (Bermuda) (Russia) overriding and allowed the aircraft nose
up upset. Lack of PIC's skill of aircraft
upset recovery resulted in significant
deceleration, spatial disorientation and
aircraft steep dive (pitch down angle up to
75°) down to ground impact.
Go-around flight maneuver was caused by
the aircraft non-landing setting running
out to the RWY that was caused by "Map
shift" effect (aircraft position indication
error by airbone systems) by the rate of 4
km, the crew disability to perform
composite aircraft navigation and
navigation with adequate accuracy as well
as absence of ATM active assistance
during long monitoring of significant
deviations from the approach pattern.
The mentionned contributing factors
include the following ones:
- not identification of the autopilot
overriding by the crew and late
interference with aircraft that resulted in
aircraft nose up upset;
- possible effect of somatic
gravitational illusions.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 53 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
B737-3YO 22/11/2015 Osh Accident Substantial 0 At 23:56L the captain consulted with
(turbofan) - EX- airport damages weather forecasters at Osh, who indicated
37005 (Russia) from hard the weather would be better than
(Kyrgyzstan) landing METARs and SPECIs suggested and
and RWY advised the weather would improve to a
excursion visibility of 600 meters horizontally and
200 feet vertically at 00:30L. The captain
therefore decided to depart at 00:00L Nov
22nd 2015. The aircraft was finally taxiing
for departure from Osh at 01:04L, during
taxi the actual weather report from Osh
was received and indicated visibility of
200-800 meters horizontally and 200 feet
vertically sometimes reducing to 100 feet.
Following departure at 01:08L Air Traffic
Control advised at 01:18L visibility at Osh
had improved to 1700meters horizontally
and 200 feet verticaly.
While descending to FL070 at Osh at
01:38L ATC advised visibility was 900
meters horizontally and 100 feet vertically
and queried whether the aircraft would
commence the approach. The crew
continued the approach.
At 01:43L ATC advised the visibility had
reduced to 500 meters horizontally and
100 feet vertically.
At 01:44L the crew advised they were
going around, the aircraft however
collided with the runway within the touch
down zone at +3.96G. While climbing out
the crew queried weather and
subsequently decided to return to
Bishkek. The aircraft climbed to FL150, the
crew intended to climb higher. However,
as result of the impact on the runway two
hydraulic systems had failed and the right
hand engine showed increasing problems
including decreasing oil pressure and
rising EGT. The crew assessed their
options to divert to Bishkek and decided
to land at Osh despite the weather
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 54 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
conditions present. The right hand engine
was shut down and the aircraft returned
to Osh for an emergency landing, touched
down about 1063 meters past the runway
threshold and overran the end of the
runway by 529 meters.
The MAK reported 6 passengers received
"moderate" injuries during the landing, 5
passengers received minor injuries during
the landing.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 55 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
B737-800 19/03/2016 Rostov-on- Accident Destroyed 62 On March 19, 2016 a Boeing 737-800
(turbofan) - A6- Don aircraft registered A6-FDN operated by Fly
FDN (United airport Dubai, while executing a recurrent
Arab Emirates) (Russia) approach at night time in IMC at Rostov-
on-Don Airdrome with landing heading
218˚, the crew went around from the
height of 220 m (4.5 KM before the
runway) with vertical speed of up to 20
mps setting the engines to max
takeoff/goaround thrust. Both approaches
(from the height of about 600 m) were
performed with autopilot and autothrottle
disengaged in flight director mode
without significant heading or altitude
deviations from the glideslope.
One of the possible causes of the go-
around decision could have been the 20 kt
increase of indicated speed to as much as
176 kt within 3 seconds, which might have
been an indication of windshear.
In the course of the go-around the crew
set flaps to 15˚ and retracted the landing
gear.
At a height of 1900 ft, (approx. 600m)
after reaching a pitch of 18˚, the PF
pushed on the control column, which led
to a decrease in vertical acceleration of up
to 0.5, increase in forward speed and,
consequentially, automatic retraction of
flaps from 15˚ to 10˚ at a speed of over
200 kt.
The short term decrease in engine thrust
within 3 seconds resulted in decreasing
speed and flap extension to 15˚, although
the following crew inputs to regain max
takeoff/goaround thrust led to speed
increase and reiterated automatic flaps
retraction to 10˚. The flaps remained in
the latter configuration until impact.
The PF, by pulling up the control column,
continued climbing with a vertical speed
of as much as 16 mps.
At a height of 900 m, there was a
simultaneous control column nose down
input and stabilizer nose down deflection
from -2.5 deg to +2.5 deg (the FDR
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 56 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
recorded a nose down stabilizer input
from the stabilizer trim switch of the
control wheel lasting 12 sec), as a result
the aircraft, having climbed to about 1000
m, turned into descent with negative
vertical acceleration of -1g.
The following crew recovery actions did
not allow to avoid an impact with the
ground. The aircraft hit the runway about
120 m from the threshold with a speed of
over 600 km/h and over 50˚ nose down
pitch.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 57 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
B777-31H 03/08/2016 Dubai Accident Destroyed 1 As the flight neared Dubai, the crew
(turbofan) - A6- (United received the automatic terminal
EMW (United Arab information service (ATIS) Information
Arab Emirates) Emirates) Zulu, which included a windshear warning
for all runways.
During the approach, at 0836:00, with the
autothrottle system in SPEED mode, as
the Aircraft descended through a radio
altitude (RA) of 1,100 feet, at 152 knots
IAS, the wind direction started to change
from a headwind component of 8 knots to
a tailwind component. The autopilot was
disengaged at approximately 920 feet RA
and the approach continued with the
autothrottle connected. As the Aircraft
descended through 700 feet RA at
0836:22, and at 154 knots IAS, it was
subjected to a tailwind component which
gradually increased to a maximum of 16
knots.
At 0837:07, 159 knots IAS, 35 feet RA, the
PF started to flare the Aircraft. The
autothrottle mode transitioned to IDLE
and both thrust levers were moving
towards the idle position. At 0837:12, 160
knots IAS, and 5 feet RA, five seconds
before touchdown, the wind direction
again started to change to a headwind.
As recorded by the Aircraft flight data
recorder, the weight-on-wheels sensors
indicated that the right main landing gear
touched down at 0837:17, approximately
1,100 meters from the runway 12L
threshold at 162 knots IAS, followed three
seconds later by the left main landing
gear. The nose landing gear remained in
the air.
At 0837:19, the Aircraft runway
awareness advisory system (RAAS) aural
message “LONG LANDING, LONG
LANDING” was annunciated.
At 0837:23, the Aircraft became airborne
in an attempt to go-around and was
subjected to a headwind component until
impact. At 0837:27, the flap lever was
moved to the 20 position. Two seconds
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 58 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
later the landing gear lever was selected
to the UP position. Subsequently, the
landing gear unlocked and began to
retract.
At 0837:28, the air traffic control tower
issued a clearance to continue straight
ahead and climb to 4,000 feet. The
clearance was read back correctly.
The Aircraft reached a maximum height of
approximately 85 feet RA at 134 knots IAS,
with the landing gear in transit to the
retracted position. The Aircraft then
began to sink back onto the runway. Both
crewmembers recalled seeing the IAS
decreasing and the Copilot called out
“Check speed.” At 0837:35, three seconds
before impact with the runway, both
thrust levers were moved from the idle
position to full forward. The autothrottle
transitioned from IDLE to THRUST mode.
Approximately one second later, a ground
proximity warning system (GPWS) aural
warning of “DON’T SINK, DON’T SINK” was
annunciated.
One second before impact, both engines
started to respond to the thrust lever
movement showing an increase in related
parameters.
At 0837:38, the Aircraft aft fuselage
impacted the runway abeam the
November 7 intersection at 125 knots,
with a nose-up pitch angle of 9.5 degrees,
and at a rate of descent of 900 feet per
minute. This was followed by the impact
of the engines on the runway. The three
landing gears were still in transit to the
retracted position. As the Aircraft slid
along the runway, the No.2 engine-pylon
assembly separated from the right hand
(RH) wing. From a runway camera
recording, an intense fuel fed fire was
observed to start in the area of the
damaged No.2 engine-pylon wing
attachment area. The Aircraft continued
to slide along the runway on the lower
fuselage, the outboard RH wing, and the
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 59 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
No.1 engine. An incipient fire started on
the underside of the No.1 engine.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 60 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
DC-8-63 15/02/1992 Swanton Accident Destroyed 4 ATI Flight 805 departed from Seattle at
(turbofan) - (USA) 23:20 for a flight to Toledo. The 1st officer
N794AL (USA) was flying the ILS approach to runway 07.
For undetermined reasons, he failed to
properly capture the ILS localizer and/or
glide slope during the approach. At 03:13
the captain decided to carry out a go-
around. The aircraft was vectored onto a
base leg and given a heading of 100deg to
intercept the final approach course again.
With a 35 knots crosswind (at 180deg) on
the approach the 1st officer had trouble
capturing the localizer/glide slope. At
03:24, as the 1st officer was attempting to
stabilize the approach, 3 GPWS glide slope
warnings and sink rate warnings sounded.
The captain took over control at 03:24:17
and performed another missed approach
manoeuvre. He became spatially
disoriented and inadvertently allowed an
unusual attitude to develop with bank
angles up to 80deg and pitch angles up to
25deg. When in a nose-low and left bank
angle attitude, control of the airplane was
transferred back to the 1st officer who
began levelling the wings and raising the
nose of the airplane. Impact with the
ground occurred before the unusual
attitude recovery was completed.
PROBABLE CAUSE: "The failure of the
flight crew to properly recognize or
recover in a timely manner from the
unusual aircraft attitude that resulted
from the captain's apparent spatial
disorientation, resulting from
physiological factors and/or a failed
attitude director."
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 61 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
Swearingen 11/10/2001 Shamatta Accident Destroyed 2 Approaching Shamattawa, the crew began
SA226 TC wa, a descent to the 100 nautical mile
Metro II Canada minimum safe altitude of 2300 feet above
(turboprop) - C- sea level (asl) and, when clear of an
GYPA (Canada) overcast cloud layer at about 3000 feet
asl, attempted a night, visual approach to
Runway 01. The aircraft was too high and
too fast on final approach and the crew
elected to carry out a missed approach.
Approximately 30 seconds after the power
was increased, at 2333, the aircraft flew
into trees slightly to the left of the runway
centreline and about 2600 feet from the
departure end of Runway 01. The aircraft
was equipped with a cockpit voice
recorder (CVR) that indicated the crew
were in control of the aircraft; they did
not express any concern prior to impact.
The aircraft broke apart along a wreckage
trail of about 850 feet.
The loss of visual references as the aircraft
accelerated along the runway and past the
lights of the community were ideal for the
onset of somatogravic illusion in the pilot
flying. Even 7 seconds prior to impact, the
captain believed that he was climbing to
1000 feet above ground level. The
captain's performance was consistent
with his being unable to distinguish the
imposed acceleration as the aircraft speed
increased from that of gravity and,
although he probably thought the aircraft
was climbing, it was not.
The first officer may also have been
influenced by the somatogravic illusion.
During the 30 seconds of the missed
approach, his tasks were to react to the
captain's commands and to monitor the
instruments. Apparently the first officer
did not observe anything remarkable or
he would have alerted the captain that
the aircraft was not climbing. It is possible
that he was distracted by the sudden
sound of the NDB identifiers just after the
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 62 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
missed approach was initiated. The NDB
receiver was turned off just prior to
impact, and since the control head is on
the first officer's side of the cockpit, it was
likely he who turned the NDB off. Given
the short duration of the overshoot and
the tasks that the first officer was
performing, it is probable that he had a
false perception that the aircraft was
climbing.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 63 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
A/C Type & Date Location Accident or A/C Fatalities Investigation finding
registration (DD/MM/YYYY) incident damages
DHC-8-103 02/12/2010 Svolvær Serious None 0 The incident probably occurred as a result
(turboprop) - Airport incident of the aircraft suddenly being subjected to
LN-WIU Helle significant variations in wind direction
(Norway) (Norway) and/or wind speed. The wind also
probably impacted the aircraft during the
seconds the crew had to regain control.
Information about observed wind has lead
AIBN to believe that the aircraft may have
been exposed to a significant wind shear,
for example as a result of sudden loss of
headwind or maybe even tailwind, due to
a gust from a CB in the area. It is also
possible that this came in an unfortunate
combination with mechanical turbulence
in the area due to the south-westerly gale.
The Accident Investigation Board assessed
that the risk of spatial disorientation was
great in this instance, as the Commander
flew on visual without visible horizon and
in complete darkness. In particular, the
powerful longitudinal acceleration during
the initial increase in engine power could
have caused so-called somatogravic
illusion, a false sense of the nose of the
aircraft raising. A possible illusion could
explain some apparent discrepancies and
circumstances which otherwise do not
appear logical in this case. Specifically why
the crew did not perceive just how low
they were, why they reacted the way they
did when exposed to a wind shear, and
why they ended up with different
perceptions of what had actually
happened.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 64 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Category 2 occurrences:
A/C Type & Date Location Accident A/C Fataliti Investigation report finding
registration or damages es
incident
A320 27/11/2008 Canet-plage Accident Destroyed 7 The accident was caused by the loss of control
(turbofan) - (France) of the aeroplane by the crew following the
D-AXLA improvised demonstration of the functioning
(Germany) of the angle of attack protections, while the
blockage of the angle of attack sensors made it
impossible for these protections to trigger.
The crew was not aware of the blockage of the
angle of attack sensors. They did not take into
account the speeds mentioned in the
programme of checks available to them and
consequently did not stop the demonstration
before the stall.
The loss of control was caused by a thrust
increase performed with a full pitch-up
horizontal stabilizer position. This pitch trim
position combined with the high thrust
resulted in a lack of pitch down authority to
the pilot. The PF made no inputs on the
horizontal stabilizer nor did he reduce the
thrust; the PNF did not intervene. This seems
to indicate that none of them were aware that
the automatic trim system, which relieves the
pilot of any actions to trim the aeroplane, was
no longer available.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 65 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
B737-800 - 25/02/2009 Amsterdam Accident Destroyed 9 During the accident flight, while executing the
TC-JGE (Netherland approach by means of the instrument landing
(Turkey) s) system with the right autopilot engaged, the
left radio altimeter system showed an incorrect
height of -8 feet on the left primary flight
display. This incorrect value of -8 feet resulted
in activation of the ‘retard flare’ mode of the
autothrottle, whereby the thrust of both
engines was reduced to a minimal value
(approach idle) in preparation for the last
phase of the landing.[...] The right autopilot
(using data from the right radio altimeter)
followed the glide slope signal. As the airspeed
continued to drop, the aircraft’s pitch attitude
kept increasing. The crew failed to recognise
the airspeed decay and the pitch increase until
the moment the stick shaker was activated.
Subsequently the approach to stall recovery
procedure was not executed properly, causing
the aircraft to stall and crash.
Recovery behaviour:
Investigation was also performed into the
recovery characteristics of the B737-800 at the
moment of the approach to stall warning
onset, with and without autopilot engaged.
Maximum thrust was selected 1 second after
the stickshaker warning to account for reaction
time. The aircraft was flown with autopilot
engaged and the stabiliser trimmed until an
airspeed slightly above the approach to stall
warning onset speed. With this speed the
stabiliser reached its airplane nose-up stop (full
nose-up electrical trim) and could not be
trimmed further in the nose-up direction. This
was also the case with flight TK1951. Because
of the stabiliser’s maximum nose-up moment
and corresponding low speed just above the
stall speed, which was beyond the FAR 25.103
criteria, the effectiveness of the elevator might
be less than demonstrated during certification
tests.
With the selection of maximum thrust, with
underwing engines, an additional pitch-up
moment is produced. If the speed is sufficiently
low, nose down trimming is necessary to
maintain full pitch authority. This situation was
confirmed during the M-Cab sessions.
Manual recovery
During the manual recovery, under the above
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 66 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
given conditions, it was necessary to push the
control column fully forward in order to
prevent the pitch value from becoming higher
than the pitch limit indicator leading to aircraft
stall. As the recovery progressed it was not
always possible to maintain the aircraft pitch at
or below the pitch limit indicator without
trimming the stabiliser in most cases, but
adequate elevator authority was available for
at least 40 seconds before trimming was
required. Control forces were maximum
between 30-50 pounds and such that with one
hand full forward control column deflection
was possible. Evaluations of various recovery
techniques showed that timely application of
thrust could ensure recovery after stick shaker.
In the event that thrust was not applied within
a few seconds of stick shaker, the airplane
could still be recovered by making control
inputs to prevent the airplane from stalling.
A330 01/06/2009 Atlantic Accident Destroyed 228 The accident resulted from the following
(turbofan) - F- ocean succession of events:
GZCP (France) - Temporary inconsistency between the
airspeed measurements, likely following the
obstruction of the Pitot probes by ice crystals
that, in particular, caused the autopilot
disconnection and the reconfiguration to
alternate law;
- Inappropriate control inputs that destabilized
the flight path;
- The lack of any link by the crew between the
loss of indicated speeds called out and the
appropriate procedure;
- The late identification by the PNF of the
deviation from the flight path and the
insufficient correction applied by the PF;
- The crew not identifying the approach to stall,
their lack of immediate response and the exit
from the flight envelope;
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 67 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
- The crew’s failure to diagnose the stall
situation and consequently a lack of inputs that
would have made it possible to recover from it.
MD-83 24/07/2014 Gossi region, Accident Destroyed 116 The aeroplane took off at night from
(turbofan) - Mali Ouagadougou airport at about 1 h 15 bound
EC-LTV for Algiers. During the climb, the crew made
(Spain) several heading changes to avoid a stormy area
before reaching cruise level FL 310. A few
minutes later, the aeroplane’s speed, piloted
by the autothrottle, decreased due to the
obstruction of the pressure sensors on the
engine nose cones, likely by ice crystals. The
autopilot then progressively increased the
aeroplane’s pitch attitude to maintain the
altitude, until the aeroplane stalled. The
aeroplane’s stall was not
recovered. The aeroplane maintained its nose-
up attitude and left bank while the control
surfaces remained mainly deflected in a pitch-
down attitude and with a right bank. The
aeroplane struck the ground at high speed.
The accident resulted from a combination of
the following events:
- non-activation by the crew of the engine’s
anti-icing system ;
- obstruction of the PT2 pressure sensors, likely
by ice crystals, leading to erroneous EPR values
that caused the autothrottle to limit the thrust
delivered by the engines below the level of
thrust required to maintain FL310 ;
- the crew’s late reaction to the decrease in
speed and to the erroneous EPR values,
possibly linked to the workload associated with
avoiding the convective system and to the
difficulties in communicating with air traffic
control ;
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 68 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
- the crew’s lack of reaction to the appearance
of buffet, the stickshaker and the stall warning
;
- the absence of appropriate flight control
inputs by the crew to recover from the stall
situation.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 69 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Appendix 2: Synthesis of the responses to the questionnaire sent to large aeroplanes
manufacturers – RMT.0647
1) General questions
a. Difficulties faced during go-around (G/A) come from the following factors:
— When aircraft (a/c) are not provided with attitude limitation function,
— When a stabiliser trim control system is not integrated with an elevator control,
— High pitch-up moment on two-engined a/c with engines under the wing,
— High thrust/weight ratio on two-engined a/c at the end of a flight: higher pitch rates than usual, high
pitch values, and high vertical speeds,
— When full thrust is applied during G/A, excessive climb speed can be reached very quickly, making it
difficult for flight crews to perform the activities related to the G/A procedure: not compatible with time
available (high workload in short time), source of somatogravic illusion,
— G/A could be associated with a disruptive element, before or during the application of thrust, which
startles the crew (e.g. unexpected ATC constraints, automatic system inputs which are not in line with
the G/A, unfavourable meteorological environment),
— High work load phase,
— Inoperative CRM and lack of PM,
— Inadequate training and knowledge of systems; pilots are not comfortable, they rarely practice G/A in
the a/c; they should be trained to perform most dynamic G/A on actual light-weight a/c rather than on
simulators,
— Human factors issue because pilots do not anticipate sufficiently the G/A option during approach.
Some manufacturers highlighted the importance of a better training; they have taken action to recommend
better training:
— Surprise effects should be included in the training,
— Different scenarios should be used, AEO in addition to OEI,
— Emphasising trust in instruments,
— Communication and task sharing between PF-PM,
— Somatogravic illusion should be trained (recognise and mitigate).
Three manufacturers have developed a reduced G/A thrust function to mitigate the above issues.
One regional turboprop manufacturer stated it did not have problems with this topic. Another manufacturer of
turboprop and turbofan (fuselage-mounted) also stated it has no problems, however, the turbofan aircraft
have a function which can reduce thrust and limit pitch attitude.
b. Introduction of thrust reduction systems
3 manufacturers introduced such systems.
Normally, maximum thrust can still be selected by the flight crew (FC) (but one manufacturer did not specify if
this is possible with its design).
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 70 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
c. Introduction of features which can ensure pitch trim control for the go-around phase or other flight
phases
3 manufacturers have designs with flight-envelope-protection functions which provide some kind of protection
against miss-trim. The details on how these functions work and their availabilities can vary between types and
manufacturers.
d. Positive and negative aspects of introducing a go-around thrust reduction system
Positive aspects:
— less energy during light weight G/A,
— less pitch attitude during the G/A,
— less acceleration during the G/A,
— more time available for the pilots,
— improved pilots workload,
— reduced probability of loss of control (LOC) during G/A due to situational awareness enhancement and
reduction of spatial disorientation,
— same standards/training as for heavier aeroplanes,
— comfort for pilot and passengers.
Negative aspects:
— controls/logics needed to allow full thrust application which introduces uncertainty,
— crew will not get used to proper associated feeling ‘the lighter the a/c, the more energetic the G/A’,
— reducing the frequency of cases when pilots feel high thrust application during G/A (not limited by a
system) negatively affects pilots readiness/proficiency,
— analysing adapted power is adding workload to the crew,
— development costs involved,
— implementation costs involved,
— training definition and implementation costs involved,
— solutions may involve multidisciplinar areas (flight controls, engines - FADEC, flight guidance, etc.),
— solutions may require higher levels of assurance for some systems (design assurance level),
— design integration to avoid unintended consequences is always a challenge with new systems,
— difficult system integration especially for types which rely on manual power setting (with a risk that the
wrong setting is used),
— financial burden for both the manufacturer and the operators (with, according to the 2 turboprop
manufacturers, no associated safety improvement)
2) G/A thrust reduction systems
a. Aeroplanes NOT equipped with a go-around thrust reduction (GATR) system
3 manufacturers have implemented it on some of their types.
5 manufacturers have not decided to implement a function, 1 of them is considering it.
When not implemented the reasons provided are:
— No reported incident or accident,
— Regional operations have reduced exposure to the risk (CG/weight envelope),
— Lack of regulation on G/A thrust reduction systems,
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 71 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
— The efforts to implement a function,
— Dot not see the necessity of such system (turboprop),
— Production stopped,
— Climb capability not critical,
— Cost vs fleet size and usage,
— Required hardware and software modifications on older generation aeroplanes,
— Mitigation means found through procedure on some types (e.g. TOGA then reduction to CLB) and
communications to operators,
— From a turboprop manufacturer: pilots should be trained to adapt the engine power to the path
requirements. So the available flying cues should allow the pilot to adapt the power to the desired path
and speed.
b. Aeroplanes equipped with a GATR system
Info on system implementation by 3 manufacturers:
1 manufacturer developed the function recently, it has been certified first as a modification; first on the 2 most
recent types, and then on some older types where the design impact remains acceptable. For the 2 most
recent types, retrofit has been done and all customers take the option on production aeroplanes. For other
types where the modification has been certified, the option is available in production and retrofit is possible;
the operator decides after considering their mixed fleet strategy.
Criteria used to establish whether the system should be implemented: thrust/weight ratio, climb capability at
all weights, industrial complexity to address all configurations (for retrofit), fleet size (for a/c not anymore in
production). All a/c, including quads, were potential candidates for the introduction of the function.
Figures are provided on the number of a/c equipped.
1 manufacturer developed the function earlier and has implemented it on all its production aeroplanes. It was
certified as part of the TC/ATC.
No figures provided on the number of a/c equipped.
1 manufacturer developed the function on one of its two types as part of the original type design.
Cost assessments (only 1 manufacturer replied):
Development costs:
On existing types: high non recurring cost (NRC) because it requires specific (engine and systems) supplier
development costs, specific integration work, ground testing, and flight test program. No figures are provided.
New types: Cost is less because of part of the overall development and validation work plan.
Cost of installation on a newly manufactured a/c:
No additional recurring cost (RC). Only installation of relevant software standards (ATA22, 31, 73) are needed.
No hardware change to the a/c.
Cost of installation of the system on already manufactured a/c (retrofit):
Need to retrofit relevant software standards on some types. RC for the operator is very limited.
Other a/c types (the most recent ones) have the function capability in EIS standards.
Maintenance costs
None
Costs for crew training
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 72 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Maintenance:
Initial: none; Recurrent: none.
Pilots:
Initial: none specified, it is part of the SOP. Recurrent: Training centres define their programme; corresponding
costs cannot be assessed.
Issues encountered with the go-around thrust reduction system:
None reported by the responders.
Frequency of use of the function by the pilots: unknown.
Benefits:
Safety: No statistics available. It is expected that, with the soft G/A as the SOP, events with excessive energy as
one of primary causes should be prevented by a correct application of the soft G/A mode.
Fuel consumption: Marginal effect.
Time saving: Not assessed, it is very dependent on the operational parameters (airport, procedures, weight,
altitude, etc.)
Go-around thrust reduction system availability
Manual mode: Yes (but A/TR must be armed on some a/c)
Autopilot selected mode: Yes (as long as A/TR is armed or ‘On’ on some a/c)
Autopilot managed mode: Yes (if applicable)
With the auto-thrust function on or off? Armed/active or not?: Armed or on.
3) Pitch trim control systems
a. Which ones of your aeroplanes types are equipped with an automatic pitch trim function (either in
manual control or autopilot mode), which ones are not?
All a/c have a kind of automatic pitch trim function, however, there are different designs (e.g. using a movable
horizontal stabilizer or elevator trim tabs).
The availability of the auto trim function is also variable. On some a/c it is available in all modes, on some a/c it
is available only when autopilot is engaged. In case of degraded flight control modes, the function may be lost.
b. Feature limiting the horizontal stabiliser nose up travel at low speed?
6 manufacturers have types with some kind of travel-limitation functions, however, the way they work is
variable.
2 manufacturers have systems without limitation (turboprop a/c using elevator tabs).
A/c with fly-by-wire design and flight envelope protection can use various parameters to inhibit the pitch
control demand (AOA, pitch, speed, etc.).
Availability of the feature: For a/c equipped with this feature, it is available in manual and autopilot modes.
No detail was provided on the cases where this feature would not be available. It is understood that the
feature is available as long as the automatic pitch trim function is not inhibited or lost in normal cases. It may
be lost in failure cases, this depends on the design.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 73 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
c. Is there a means, on your aeroplanes, to alert the flight crew when the pitch trim is in an
inappropriate position for the flight phase (e.g. excessive nose up trim position)? Please describe which kind
of alert (aural, visual…) is provided to the flight crew for the different piloting modes (manual, autopilot).
No a/c has such a specific alert. However, some aircraft have other means to detect abnormal pitch trim
position like:
— Stabiliser cannot be inappropriately positioned (i.e. in a position that could somehow affect any pitch
manoeuvre) per design,
— Alerts in case of failure conditions (e.g. jam, runaway, mis-trim, etc.),
— Alerts in case of abnormal configuration (e.g. T/O configuration, out of trim).
d. For your aeroplanes, did you investigate longitudinal control characteristics beyond the current
CS 25.143 and 25.145 requirements, in particular cases where the pitch trim is commanded at its maximum
nose up position (either manually or by an automatic trim system)? If yes, please explain what has been
investigated and the finding.
Manufacturers either did not investigate characteristics beyond the certification requirements, they decline to
provide information, or the investigations were limited to practicable manoeuvres and expected THS settings.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 74 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Appendix 3: Evaluation of the proportion of large aeroplanes
(operated by EASA Member States operators in commercial air transport)
that are equipped with a system reducing the G/A thrust
EASA evaluated the proportion of large aeroplanes operated by EASA Member States operators that are or will
be equipped with a system reducing the G/A thrust.
Part A: Current fleet of in-service aeroplanes
The information on the total number of aeroplanes from a database16 was integrated with information
provided by manufacturers who specified which aeroplane types are actually equipped. The information below
provides a snapshot view on the current fleet as of 10 January 2017.
The following criteria were used when selecting the information from the database:
1) Aeroplanes certified in the CS-25 category (large aeroplanes)
2) Aeroplanes operated in commercial air transport (CAT)
3) Aeroplanes operated by EASA MS operators
The following table shows the aeroplane manufacturers, the corresponding aeroplane types, the aeroplanes
equipped with a go-around thrust reduction system, and the ones which are not equipped.
Without With
Aeroplane Manufacturer Aeroplane Type system system
Aerospatiale Corvette 2
Airbus A300 26
Airbus A310 6
Airbus A318 28
Airbus A319 488
Airbus A320 892
Airbus A321 301
Airbus A330 228
Airbus A340 130
Airbus A350 8
Airbus A380 36
Aircraft Industries - Let L-410 34
Antonov An-26 11
ATR ATR 42 74
ATR ATR 72 211
BAE SYSTEMS (Avro) RJ Avroliner 60
16
Ascend Fleets from FlightGlobal
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 75 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Without With
Aeroplane Manufacturer Aeroplane Type system system
BAE SYSTEMS (HS) 125/Hawker 10
BAE SYSTEMS (HS) 146 23
BAE SYSTEMS (HS) ATP 36
BAE SYSTEMS (Jetstream) Jetstream 31 30
BAE SYSTEMS (Jetstream) Jetstream 41 22
Beechcraft Corp King Air 350 12
Boeing 717 18
Boeing 727 4
Boeing 737 (CFMI) 209
Boeing 737 (JT8D) 1
Boeing 737 (NG) 840
Boeing 747 3 145
Boeing 757 129
Boeing 767 82
Boeing 777 201
Boeing 787 83
Boeing (McDonnell-Douglas) MD-11 14
Boeing (McDonnell-Douglas) MD-80 30
Bombardier (Canadair) Challenger 300 48
Bombardier (Canadair) Challenger 350 33
Bombardier (Canadair) Challenger 600 / 601 / 604 / 605 121
Bombardier (Canadair) Challenger 650 5
Bombardier (Canadair) CRJ Regional Jet 42
Bombardier (Canadair) CRJ1000 Regional Jet 32
Bombardier (Canadair) CRJ700 Regional Jet 17
Bombardier (Canadair) CRJ900 Regional Jet 58
Bombardier (Canadair) CSeries 7
Bombardier (Canadair) Global 5000 46
Bombardier (Canadair) Global Express/Global 6000 158
Bombardier (de Havilland) Dash 8 214
Bombardier (de Havilland) DHC-7 1
Bombardier (Learjet) Learjet 24 1
Bombardier (Learjet) Learjet 25 2
Bombardier (Learjet) Learjet 31 8
Bombardier (Learjet) Learjet 35 27
Bombardier (Learjet) Learjet 36 1
Bombardier (Learjet) Learjet 40 13
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 76 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Without With
Aeroplane Manufacturer Aeroplane Type system system
Bombardier (Learjet) Learjet 45 33
Bombardier (Learjet) Learjet 55 9
Bombardier (Learjet) Learjet 60 36
Bombardier (Learjet) Learjet 75 6
Bombardier (Shorts) 360 6
Cessna Citation Bravo 34
Cessna Citation Encore 9
Cessna Citation Excel 24
Cessna Citation II 39
Cessna Citation III 8
Cessna Citation Latitude 3
Cessna Citation S/II 4
Cessna Citation Sovereign 32
Cessna Citation Ultra 6
Cessna Citation V 5
Cessna Citation VI 2
Cessna Citation VII 9
Cessna Citation X 16
Cessna Citation XLS 118
Cessna CJ3 54
Cessna CJ4 25
Dassault Aviation Falcon 10/100 6
Dassault Aviation Falcon 20/200 6
Dassault Aviation Falcon 2000 111
Dassault Aviation Falcon 50 21
Dassault Aviation Falcon 7X 106
Dassault Aviation Falcon 8X 2
Dassault Aviation Falcon 900 88
Embraer 170 34
Embraer 175 42
Embraer 190 115
Embraer 195 61
Embraer EMB-120 Brasilia 14
Embraer ERJ-135 87
Embraer ERJ-140 9
Embraer ERJ-145 68
Embraer Legacy 450 2
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 77 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Without With
Aeroplane Manufacturer Aeroplane Type system system
Embraer Legacy 500 3
Embraer Phenom 300 57
Fairchild (Swearingen) Merlin III 1
Fairchild/Dornier Dornier 328 27
Fairchild/Dornier Dornier 328JET 19
Fokker F100 31
Fokker F50 30
Fokker F70 17
Fokker F27 5
Gulfstream Aerospace Gulfstream G280 9
Gulfstream Aerospace Gulfstream G450 24
Gulfstream Aerospace Gulfstream G550 64
Gulfstream Aerospace Gulfstream G650 33
Gulfstream Aerospace Gulfstream IV 7
Gulfstream Aerospace Gulfstream V 6
Harbin Embraer Aircraft Industry ERJ-145 7
Hawker Beechcraft 125/Hawker 73
Hawker Beechcraft Beech 1900 29
Hawker Beechcraft Hawker 400/Beechjet 400 30
Hawker Beechcraft Hawker 4000 5
Hawker Beechcraft King Air 300 4
Hawker Beechcraft King Air 350 26
Israel Aerospace Industries Astra/G100 4
Israel Aerospace Industries Gulfstream G150 6
Israel Aerospace Industries Gulfstream G200 (IAI Galaxy) 23
Mitsubishi MU-300 Diamond 1
Saab 2000 33
Saab 340 70
United Aircraft Corporation (Sukhoi) Superjet 100 4
United Aircraft Corporation (Yakovlev) Yak-40 1
United Aircraft Corporation (Yakovlev) Yak-42 1
WSK-PZL Mielec An-28/M28 12
Grand Total 5,392 1,781
Therefore, around a quarter (24.8 %) of the current fleet is equipped.
Part B: Aeroplanes to be manufactured and put into service in the next 2 years
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 78 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
This part provides a view on the level of equipment of aeroplanes to be manufactured and put into service in
the next 2 years (2017-2018). The information on the total number of aeroplanes from a database17 was
integrated with information provided by manufacturers who specified which aeroplanes are actually equipped.
The result of this assessment is used as a basis for the assessment of the future fleet provided in part C of this
appendix.
The following criteria were used when selecting the information from the database:
1) Aeroplanes certified in the CS-25 category (large aeroplanes)
2) Aeroplanes operated in commercial air transport (CAT)
3) Aeroplanes operated by EASA MS operators
4) Average age of aeroplanes between 0 and 2 years18
Another important assumption had to be made: for some Airbus types the system will remain optional, based
on customer’s request. In these cases, it was assumed that 50 % of the aeroplanes will be equipped.
17
Ascend Fleets from FlightGlobal
18
The reason why two years have been included is to have a more detailed statistical basis in order to calculate the evolution of aircraft fleet
with/without the system in the future. Indeed by taking only one year the overproduction/underproduction of one aircraft type could influence the
final result.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 79 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
With Without
Aeroplane Manufacturer Aeroplane Type Total system system
Airbus A320 12519 63 63
Airbus A321 4920 25 25
Airbus A330 16 8 8
Airbus A350 8 8 0
Airbus A380 3 3 0
Aircraft Industries - Let L-410 5 0 5
ATR ATR 42 1 0 1
ATR ATR 72 33 0 33
Beechcraft Corp King Air 350 5 0 5
Boeing 737 (NG) 141 141 0
Boeing 747 6 6 0
Boeing 777 17 17 0
Boeing 787 51 51 0
Bombardier (Canadair) Challenger 350 21 0 21
Bombardier (Canadair) Challenger 600 / 601 / 604 / 605 3 0 3
Bombardier (Canadair) Challenger 650 5 0 5
Bombardier (Canadair) CRJ1000 Regional Jet 9 0 9
Bombardier (Canadair) CSeries 7 0 7
Bombardier (Canadair) Global 5000 2 0 2
Bombardier (Canadair) Global Express / Global 6000 29 0 29
Bombardier (de Havilland) Dash 8 7 0 7
Bombardier (Learjet) Learjet 75 3 0 3
Cessna Citation Latitude 3 0 3
Cessna Citation Sovereign 2 0 2
Cessna Citation XLS 7 0 7
Cessna CJ3 4 0 4
Cessna CJ4 7 0 7
Dassault Aviation Falcon 2000 10 0 10
Dassault Aviation Falcon 7X 8 0 8
Dassault Aviation Falcon 8X 2 0 2
Dassault Aviation Falcon 900 1 0 1
Embraer 175 4 0 4
Embraer 190 3 0 3
Embraer ERJ-135 6 0 6
19
Difference due to rounding.
20
Difference due to rounding.
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 80 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
With Without
Aeroplane Manufacturer Aeroplane Type Total system system
Embraer Legacy 450 2 0 2
Embraer Legacy 500 2 0 2
Embraer Phenom 300 24 0 24
Gulfstream Aerospace Gulfstream G280 4 0 4
Gulfstream Aerospace Gulfstream G550 2 0 2
Gulfstream Aerospace Gulfstream G650 14 0 14
Hawker Beechcraft King Air 350 1 0 1
United Aircraft Corporation (Sukhoi) Superjet 100 3 0 3
WSK-PZL Mielec An-28/M28 9 0 9
Grand Total 664 321 343
This leads to the following results, that are used in part C below:
— New aeroplanes equipped: 48.34 %
— New aeroplanes not equipped: 51.66 %
Part C: Future fleet of aeroplanes
This part provides a view on the evolution of proportion of aeroplanes equipped with a G/A thrust reduction
system up to 2050. This assessment is based on the results of part A and part B of this appendix.
The proportion of aeroplanes equipped determined in part A is shown for year 2017 below. For the following
years, the new aeroplanes equipped with a system (calculated in Part B) affect gradually the final percentage
of aeroplanes (by replacing the ones leaving the in-service fleet).
As from the year 2041, the percentage of aeroplanes with/without a G/A thrust reduction system remains
stable. This prediction up to 2050 is based on assumptions and only gives an indication.
Year Without With
system system
2017 75.2 % 24.8 %
2018 73.4 % 26.6 %
2019 72.6 % 27.4 %
2020 71.9 % 28.1 %
2021 71.2 % 28.8 %
2022 70.4 % 29.6 %
2023 69.6 % 30.4 %
2024 68.9 % 31.1 %
2025 68.2 % 31.8 %
2026 67.2 % 32.8 %
2027 66.0 % 34.0 %
2028 64.9 % 35.1 %
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 81 of 82
An agency of the European Union
European Aviation Safety Agency NPA 2017-06
7. Appendices
Year Without With
system system
2029 63.8 % 36.2 %
2030 63.0 % 37.0 %
2031 62.1 % 37.9 %
2032 61.2 % 38.8 %
2033 59.9 % 40.1 %
2034 58.6 % 41.4 %
2035 57.0 % 43.0 %
2036 55.7 % 44.3 %
2037 54.9 % 45.1 %
2038 54.3 % 45.7 %
2039 53.6 % 46.4 %
2040 52.9 % 47.1 %
2041 52.4 % 47.6 %
2042 51.9 % 48.1 %
2043 51.7 % 48.3 %
2044 51.7 % 48.3 %
2045 51.7 % 48.3 %
2046 51.7 % 48.3 %
2047 51.7 % 48.3 %
2048 51.7 % 48.3 %
2049 51.7 % 48.3 %
2050 51.7 % 48.3 %
TE.RPRO.00034-005 © European Aviation Safety Agency. All rights reserved. ISO 9001 certified.
Proprietary document. Copies are not controlled. Confirm revision status through the EASA intranet/internet. Page 82 of 82
An agency of the European Union