Airworthiness Directive · Amendment 39-18668 · Fuselage
The Boeing Company Airplanes
(1) This AD applies to The Boeing Company Model 737-300, -400, and -500 series airplanes, certificated in any category, identified as Group 2 in Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015.
(2) Installation of Supplemental Type Certificate (STC) ST01219SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/EBD1CEC7B301293E86257CB30045557A?OpenDocument&Highlight=st01219s) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-300, -400, and -500 series airplanes. This AD was prompted by an evaluation by the design approval holder (DAH) indicating that the aft pressure bulkhead is subject to widespread fatigue damage (WFD). This AD requires repetitive inspections of the aft pressure bulkhead web for any cracking, incorrectly drilled fastener holes, and elongated fastener holes; and related investigative and corrective actions, if necessary. We are issuing this AD to detect and correct fatigue cracking of the aft pressure bulkhead web at the "Y"-chord, which could result in reduced structural integrity of the airplane and rapid decompression of the fuselage.
Within 76,000 total flight cycles, or within 4,500 flight cycles since the most recent low frequency eddy current (LFEC) inspection accomplished in accordance with AD 2012-18-13 R1, or within 9,500 flight cycles since the most recent high frequency eddy current (HFEC) inspection accomplished in accordance with AD 2012-18-13 R1, whichever occurs latest: Do detailed and LFEC inspections from the aft side of the aft pressure bulkhead web, or do detailed and HFEC inspections from the forward side of the aft pressure bulkhead web, for any cracking, incorrectly drilled fastener hole, and elongated fastener hole, and do all applicable related investigative and corrective actions, in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015, except as required by paragraph (i) of this AD. Do all related investigative and corrective actions before further flight. If any cracking, incorrectly drilled fastener hole, or elongated fastener hole is found, before further flight, repair the aft pressure bulkhead web using a method approved in accordance with the procedures specified in paragraph (l) of this AD. Thereafter, repeat the inspections at the applicable times specified in table 10 of paragraph 1.E., “Compliance” of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015.
Within 76,000 total flight cycles, or within 4,500 flight cycles since the most recent LFEC inspection accomplished in accordance with AD 2012-18-13 R1, or within 9,500 flight cycles since the most recent HFEC inspection accomplished in accordance with AD 2012-18-13 R1, whichever occurs latest: Do detailed and LFEC inspections from the aft side of the aft pressure bulkhead, or do detailed and HFEC inspections from the forward side of the aft pressure bulkhead, for any cracking, incorrectly drilled fastener hole, and elongated fastener hole, and do all applicable corrective actions, in accordance with Part III of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015, except as required by paragraph (i) of this AD. Do all corrective actions before further flight. If any cracking, incorrectly drilled fastener hole, or elongated fastener hole is found, before further flight, repair the aft pressure bulkhead web using a method approved in accordance with the procedures specified in paragraph (l) of this AD. Thereafter, repeat the inspections at the applicable times specified in table 11 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015.
Where Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015, specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
(1) For Group 2 airplanes specified in Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015: Accomplishing the actions required by paragraph (g) of this AD terminates the inspections required by paragraph (k) of AD 2012-18-13 R1, except for stringer S-5L to S-7L and stringer S-5R to S-9R.
(2) For Group 2 airplanes specified in Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015: Accomplishing the actions required by paragraph (h) of this AD terminates the inspections required by paragraph (l) of AD 2012-18-13 R1.
