The FAA plans to mandate inspections of certain structural fittings on some Boeing 787s after learning from the company that the parts are made from the wrong material.
Revealed in a draft airworthiness directive (AD) slated for publication May 17, the issue involves floor beam fittings on the sides of some 787-9s and 787-10s.
Boeing’s specifications call for the parts to be made from Ti-6AI-4V, a grade 5 titanium alloy. But some side-of-body fittings are grade 1 or 2 commercially pure unalloyed titanium, “which has significantly reduced strength, fatigue, and damage-tolerance properties” than the specified material, the draft AD said.
The issue does not pose any immediate safety-of-flight risks. But failure of multiple adjacent fittings, either over time or due to exposure to heavy loads during rare events such as hard landing or rapid decompression, could compromise surrounding structure and systems, the FAA said.
Boeing informed operators of the issue directly in a December 2023 alert requirements bulletin. The bulletin advises operators to conduct X-ray fluorescence spectrometer inspections or swap out parts with ones that are known to comply.
The bulletin, which has not been made public, also provides recommended inspection deadlines as well as a list of affected airframes. The draft AD references the bulletin and says Boeing’s recommendations will become mandatory, but does not detail the deadlines or affected aircraft. Operators are expected to refer to the bulletin.
The AD does not explain how the mix-up happened.
Boeing did not immediately respond to Aviation Week queries.
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