Airworthiness Directive · Amendment 39-18305 · Fuselage
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series airplanes, certificated in any category.
We are superseding Airworthiness Directive (AD) 2007-16-08, which applied to all The Boeing Company Model 747-100, 747-100B, 747- 100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series airplanes. AD 2007-16-08 required repetitive inspections for cracking of the station 800 frame assembly, and repair if necessary. This new AD continues to require repetitive inspections for cracking of the station 800 frame assembly, and repair if necessary, and expands the inspection area. This AD was prompted by reports of cracks found at the forward and aft inner chord strap and angles on the station 800 frame on the left-side and right-side main entry doors. We are issuing this AD to detect and correct fatigue cracks that could extend and fully sever the frame, which could result in development of skin cracks that could lead to rapid depressurization of the airplane.
Except as required by paragraph (i) of this AD, at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2451, Revision 2, dated June 13, 2014: Do a detailed inspection for cracking in the inner chord strap, angles, and exposed web adjacent to the inner chords, and do surface and open hole high-frequency eddy current (HFEC) inspections for cracking in the inner chord strap and angles of the station 800 frame assembly between stringer 14 and stringer 30, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2451, Revision 2, dated June 13, 2014. It is not necessary to remove fasteners while performing the surface HFEC inspections. Repeat the inspections at the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2451, Revision 2, dated June 13, 2014.
If any cracking is found during any inspection required by paragraph (g) of this AD, before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (k) of this AD.
(1) Where Boeing Alert Service Bulletin 747-53A2451, Revision 2, dated June 13, 2014, specifies a compliance time “after the Revision 2 date of this service bulletin,” this AD requires compliance within the specified time after the effective date of this AD.
(2) The Condition column of paragraph 1.E., “Compliance,” of the Boeing Alert Service Bulletin 747-53A2451, Revision 2, dated June 13, 2014, refers to total flight cycles “as of the Revision 2 date of this service bulletin.” This AD, however applies to airplanes with the specified total flight cycles or total flight hours as of the effective date of this AD.
