Airworthiness Directive · Amendment 39-18397 · Fuselage
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 747-400F series airplanes, certificated in any category, as identified in paragraph 1.A., “Effectivity,” of Boeing Alert Service Bulletin 747-53A2880, dated December 3, 2014.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 747-400F series airplanes. This AD was prompted by an analysis of the production methods used to increase fatigue resistance of the upper closure fittings at the nose cargo door portal's C-3 frame, which showed that cracking could start too early to be caught in a timely manner by the inspection or maintenance program. This AD requires inspections of the upper closure fitting and connected strap and doubler at the nose cargo door portal for cracking, and related investigative and corrective actions if necessary. We are issuing this AD to detect and correct such cracking, which could result in sudden decompression and loss of the airplane's structural integrity.
Except as required by paragraph (h) of this AD: At the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2880, dated December 3, 2014, do a detailed inspection of the upper closure fitting, strap, and doubler and a surface high frequency eddy current (HFEC) inspection of the upper closure fitting at the nose cargo door portal for cracking, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2880, dated December 3, 2014. Repeat the inspections at the time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2880, dated December 3, 2014. Do the applicable related investigative and corrective actions at the times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2880, dated December 3, 2014.
(1) Where paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2880, dated December 3, 2014, refers to a compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specific compliance time after the effective date of this AD.
(2) If any crack is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2880, dated December 3, 2014, specifies to contact Boeing for appropriate action: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
