Airworthiness Directive · Amendment 39-17980 · Fuselage
the Boeing Company Airplanes
This AD applies to all The Boeing Company Model 747-200C and -200F series airplanes, certificated in any category.
We are superseding Airworthiness Directive (AD) 2010-03-05 for all the Boeing Company Model 747-200C and -200F series airplanes. AD 2010-03-05 required, for the upper chords of the upper deck floor beam of section 41, an inspection for cracking of certain fastener holes, and corrective action if necessary; and repetitive replacements of the upper chords, straps (or angles), and radius fillers of certain upper deck floor beams and, for any replacement that is done, inspections for cracking, and corrective actions if necessary. This new AD adds repetitive inspections of the upper chords of the upper deck floor beam of Section 42, repetitive replacements of the upper chords, post- replacement inspections, and corrective actions if necessary. This new AD also adds post-replacement inspections for section 41 and reduces certain compliance times. This AD was prompted by a determination that the upper deck floor beams are subject to widespread fatigue damage (WFD), the existing inspection program is not sufficient to maintain an acceptable level of safety, and the upper chords of the upper deck floor beam of section 42 are subject to the unsafe condition. We are issuing this AD to detect and correct cracking of the upper chords and straps (or angles) of the floor beams, which could lead to failure of the floor beams and consequent loss of controllability, rapid decompression, and loss of structural integrity of the airplane.
At the applicable time specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012: At stations (STA) 340 through STA 440, STA 500, and STA 520, do an open-hole high frequency eddy current (HFEC) inspection at all accessed fastener holes to detect cracking; and install new upper deck floor beam upper chords, straps, angles, and radius fillers; in accordance with Part 2 and Part 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012.
At the applicable time specified in Table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012; or within 1,500 flight cycles after March 11, 2010 (the effective date of AD 2010-03-05, Amendment 39-16188 (75 FR 5692, February 4, 2010)); whichever occurs later: Do detailed and HFEC inspections to detect cracking of the replaced upper deck floor beam chords, the floor panel attachment holes, and the permanent fastener locations of the replaced upper deck floor beam chords, in accordance with Part 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012. If no cracking is found, do the actions specified in paragraphs (h)(1) and (h)(2) of this AD.
(1) Do the detailed and HFEC inspections of the replaced upper deck floor beam chords within 3,000 flight cycles after the most recent inspection, or within 300 flight cycles after the effective date of this AD, whichever occurs later, and repeat thereafter at the applicable time specified in Table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012.
(2) Do the open-hole HFEC inspection and chord replacement required by paragraph (g) of this AD at the applicable time specified in Table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012, or within 240 flight cycles after the effective date of this AD, whichever occurs later. Repeat the inspections and replacement specified in paragraph (h) of this AD at the applicable time specified in Table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012.
At the applicable time specified in Tables 3 and 4 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012, except as required by paragraph (l) of this AD: Do the actions specified in paragraph (i)(1) or (i)(2) of this AD as applicable.
(1) At STA 540 through STA 740 for Group 1 airplanes identified in Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012: Do an open-hole HFEC inspection to detect cracking, and install new upper deck floor beam upper chord replacements, in accordance with Part 7 and Part 8 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012.
(2) At STA 540 through STA 780 for Group 2 airplanes identified in Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012: Do an open-hole HFEC inspection to detect cracking, and install new upper deck floor beam upper chord replacements, in accordance with Part 7 and Part 8 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012.
At the applicable time specified in Table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012; or within 1,500 flight cycles after March 11, 2010 (the effective date of AD 2010-03-05, Amendment 39-16188 (75 FR 5692, February 4, 2010)); whichever occurs later: Do HFEC inspections to detect cracking of the replaced upper deck floor beam chords, in accordance with Part 9 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012. If no crack is found, do the actions specified in paragraphs (j)(1) and (j)(2) of this AD.
(1) Repeat the HFEC inspections of the replaced upper deck floor beam chords thereafter at the applicable time specified Table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012.
(2) Do the open-hole HFEC inspection and chord replacement required by paragraph (i) of this AD at the applicable time specified in Table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012. Repeat the inspections and replacement, as specified in paragraph (j) of this AD, at the applicable time specified in Table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012.
If any cracking is found during any inspection required by this AD, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (o) of this AD.
Where Boeing Alert Service Bulletin 747-53A2696, Revision 1, dated April 12, 2012, specifies a compliance time “after the revision 1 date on this service bulletin,” this AD requires compliance within the specified compliance time “after the effective date of this AD.”
