Airworthiness Directive · Amendment 39-17620 · Fuselage
the Boeing Company Airplanes
This AD applies to The Boeing Company Model 747-400 and -400F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012.
We are adopting a new airworthiness directive (AD) for certain the Boeing Company Model 747-400 and -400F series airplanes. This AD was prompted by a report of cracks on airplanes prior to line number 1308 in the forward and aft inner chords of the station (STA) 2598 bulkhead, and the bulkhead upper and lower webs. This AD requires, as applicable, repetitive high frequency eddy current (HFEC) and low frequency eddy current (LFEC) inspections for cracks in the splice fitting, support frame, forward and aft inner chords, floor support, bulkhead upper web on the upper left and right side of the bulkhead, and the bulkhead lower web on the lower left side of the bulkhead and repair if necessary; and repetitive post-repair inspections and repair if necessary. We are issuing this AD to detect and correct cracks in the splice fitting, support frame, floor support, forward and aft inner chords, and the bulkhead upper and lower webs of the STA 2598 bulkhead, which could adversely affect the structural integrity of the airplane.
At the compliance time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012; except as provided by paragraph (h)(2) of this AD: Do HFEC and LFEC inspections, as applicable, for cracks in the splice fitting, support frame, floor support, forward and aft inner chords, the bulkhead upper web on the upper left and right side of the bulkhead, and the bulkhead lower web on the lower left side of the bulkhead, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012.
(1) If no cracking is found, repeat the applicable inspections specified in paragraph (g) of this AD, thereafter, at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012.
(2) If any cracking is found, do the actions specified in paragraphs (g)(2)(i) and (g)(2)(ii) of this AD.
(i) Before further flight, do the applicable repair, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012; except as provided by paragraph (h)(1) of this AD.
(ii) At the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012, do HFEC and LFEC inspections for cracks in the unrepaired structure, and do an HFEC inspection for cracks in the repaired structure; as specified in and in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012.
(A) If no cracking is found, repeat the applicable HFEC and LFEC inspections specified in paragraph (g)(2)(ii) of this AD, thereafter, at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012.
(B) If any cracking is found, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
(1) If any crack is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012, specifies to contact Boeing for appropriate action: Before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
(2) Where Boeing Alert Service Bulletin 747-53A2815, dated November 8, 2012, specifies a compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.
