AD 2012-13-08 Airworthiness Directives; The Boeing Company Airplanes

Models named: 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-400F, 747SR, 747SP series. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to The Boeing Company Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-400F, 747SR, and 747SP series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2502, Revision 1, dated June 17, 2010.

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

This paragraph restates the requirements of paragraph (f) of AD 2006-01-07, Amendment 39-14446 (71 FR 1947, January 12, 2006), with reduced compliance time for certain airplanes and revised service information. For Group 1, and Groups 3 through 6 airplanes identified in Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005, at the applicable time in paragraph (g)(1) or (g)(2) of this AD: Do detailed and high-frequency eddy current inspections for cracking of each affected tension tie and of the surrounding structure. If any cracking is found: Before further flight, do all applicable corrective and related investigative actions. Do all actions in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005; or Boeing Alert Service Bulletin 747-53A2502, Revision 1, dated June 17, 2010. Where Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005; or Boeing Alert Service Bulletin 747-53A2502, Revision 1, dated June 17, 2010; specifies to contact Boeing for repair instructions: Before further flight, repair the area using a method approved in accordance with the procedures specified in paragraph (n) of this AD. As of the effective date of this AD, only Boeing Alert Service Bulletin 747-53A2502, Revision 1, dated June 17, 2010, may be used to accomplish the actions required in this paragraph. (1) For airplanes identified in Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005, as Groups 1, 3, and 6 airplanes: Do the first inspections before the accumulation of 20,000 total flight cycles, or within 1,000 flight cycles after February 16, 2006 (the effective date of AD 2006-01-07, Amendment 39-14446 (71 FR 1947, January 12, 2006)), whichever occurs later; and repeat the inspections thereafter at intervals not to exceed 4,000 flight cycles until the modification required by paragraph (j) of this AD is accomplished. (2) For airplanes identified in Boeing Special Attention Service Bulletin 747-53-2502, dated April 21, 2005, as Group 4 and 5 airplanes: Do the first inspections before the accumulation of 17,000 total flight cycles, or within 1,000 flight cycles after February 16, 2006 (the effective date of AD 2006-01-07, Amendment 39-14446 (71 FR 1947, January 12, 2006)), whichever occurs later; and repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles until the modification required by paragraph (j) of this AD is accomplished.

This AD was prompted by reports that certain airplanes have tension ties that are susceptible to widespread fatigue damage. This AD also results from reports of cracks on the forward and aft tension tie channels at station (STA) 740 and STA 760, and a determination that initial inspection compliance times need to be reduced. We are issuing this AD to prevent tension ties from becoming severed or disconnected from the frames, which could lead to rapid in-flight decompression.

This AD supersedes AD 2006-01-07, Amendment 39-14446 (71 FR 1947, January 12, 2006).