Please find attached a Foreign State of Design Advisory document, endorsed by EASA.
This advisory document is also online at http://ad.easa.europa.eu/ad/NM-17-10 .
Should you have any questions, please contact the Agency by e-mail at
[email protected] or by fax,
No.: +49 221 89990 9515.
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[email protected]
EASA Website
(Attachment is in Acrobat PDF format)
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European Aviation Safety Agency.
FAA SPECIAL AIRWORTHINESS
Aviation Safety INFORMATION BULLETIN
SAIB: NM-17-10
SUBJ: Maintenance Practices Date: April 13, 2017
This is information only. Recommendations aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) advises registered owners, operators and
maintenance personnel of The Boeing Company Model 737, 747, 757, 767 and 777 airplanes of
procedural changes for detecting corrosion damage to the aft fuselage structure in the area of the
vacuum waste tanks.
At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness
directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.
Background
We have received numerous reports of corrosion damage to the aft fuselage structure in the area of
the vacuum waste tanks on Model 777 airplanes. This corrosion has been attributed to insufficient
clean up and neutralization of leakage and spillage from the vacuum waste system. These reports
document that an initial finding of corrosion damage is often followed within the year by corrosion
found in close proximity. The waste material from a vacuum waste system spill or leak is acidic and
corrosive to the airplane structure, such as skin, stringers, and frames. The waste material erodes the
corrosion inhibiting compound and the protective finishes, which causes areas of bare structure that
are more susceptible to corrosion.
While the reports of corrosion have been limited to Model 777 airplanes, Boeing believes the
Model 737, 747, 757, and 767 airplanes are subject to the same issue. To minimize and address this
corrosion, Boeing is revising the related aircraft maintenance manuals (AMMs) and structural repair
manuals (SRMs), as listed in Table 1 of this SAIB. The revisions include adding procedures for
neutralizing vacuum waste; defining the correct procedures for containing, cleaning, and neutralizing
vacuum waste; and adding procedures for the inspection for and removal of corrosion, and
re-application of protective coatings.
Recommendation
The FAA recommends that all owners and operators of the affected airplanes incorporate the revised
AMM and SRM procedures when they become available. The planned release dates are included in
Table 1 of this SAIB.
For Further Information Contact
Julie Moon, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S,
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356;
telephone: 425-917-6427; fax: 425-917-6590; email:
[email protected].
1
Table 1
2