Airworthiness Directive · Amendment 39-17971 · Nacelles/pylons
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 747-8 and 747-8F series airplanes; certificated in any category; having a variable number identified in paragraph 1.A., “Effectivity,” of Boeing Alert Service Bulletin 747-54A2238, dated January 31, 2014; and variable number RC573.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-8 and 747-8F series airplanes. This AD was prompted by an analysis by the manufacturer, which revealed that certain fuse pins for the strut-to-wing attachment of the outboard aft upper spar are susceptible to migration in the event of a failed fuse pin through bolt. This AD requires replacing the fuse pins for the strut-to-wing attachment of the outboard aft upper spar with new fuse pins, and replacing the access cover assemblies with new access cover assemblies. We are issuing this AD to prevent migration of these fuse pins, which could result in the complete disconnect and loss of the strut-to-wing attachment load path for the outboard aft upper spar. The complete loss of an outboard aft upper spar strut-to-wing attachment load path could result in divergent flutter in certain parts of the flight envelope, which could result in loss of control of the airplane.
Within 48 months after the effective date of this AD: Replace the fuse pins for the outboard aft upper spar and the access cover assemblies on struts Nos. 1 and 4, with new fuse pins and access cover assemblies, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2238, dated January 31, 2014.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
