Airworthiness Directive · Amendment 39-16022 · Fuselage
Boeing Model 747 Airplanes
This AD applies to Boeing Model 747 airplanes, certificated in any category, as specified in paragraph (c)(1) or (c)(2) of this AD, as applicable.
(1) Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes, as identified in Boeing Alert Service Bulletin 747-53A2732, dated August 28, 2008.
(2) Boeing Model 747-400, 747-400D, and 747-400F series airplanes, as identified in Boeing Alert Service Bulletin 747-53A2753, dated August 28, 2008.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 747 airplanes. This AD requires repetitive inspections for cracking of the fuselage frames in section 41, and corrective actions if necessary. This AD results from reports of cracking in fuselage frames made of 2024 aluminum alloy that were installed during previous modification of the frames in section 41 and during production. We are issuing this AD to detect and correct frame cracks, which could result in cracking of the adjacent fuselage skin and consequent rapid decompression of the airplane.
Comply with this AD within the compliance times specified, unless already done.
At the applicable compliance time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2732 or 747-53A2753, both dated August 28, 2008, as applicable, do the detailed inspection for cracking of the fuselage frames in section 41, and do all applicable corrective actions, by accomplishing all the actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2732 or 747-53A2753, both dated August 28, 2008, as applicable; except as provided by paragraphs (h) and (i) of this AD. Repeat the inspection at intervals not to exceed those specified in paragraph 1.E. of Boeing Alert Service Bulletin 747-53A2732 or 747-53A2753, both dated August 28, 2008, as applicable. If any crack is found, do all corrective actions before further flight.
Note 1: As specified in Boeing Alert Service Bulletins 747-53A2732 and 747-53A2753, both dated August 28, 2008, an optional special detailed inspection behind the P14 and P15 electrical terminal panels using the borescope may be done.
(h) Where Boeing Alert Service Bulletins 747-53A2732 and 747-53A2753, both dated August 28, 2008, recommend an initial inspection threshold relative to the date on Boeing Alert Service Bulletins 747-53A2732 and 747-53A2753, both dated August 28, 2008; this AD requires the initial inspection threshold relative to the effective date of this AD.
(i) If any crack is found during any inspection required by this AD, and Boeing Alert Service Bulletins 747-53A2732 and 747-53A2753, both dated August 28, 2008, specify to contact Boeing for appropriate action: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
