Airworthiness Directive · Amendment 39-17190 · Fuselage
The Boeing Company Airplanes
Superseded. A later AD replaced this one: AD 2012-18-13 R1. Comply with the one in force.
This AD applies to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes; certificated in any category.
We are superseding an existing airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. That AD currently requires repetitive inspections to detect cracking in the web of the aft pressure bulkhead at body station 1016 at the aft fastener row attachment to the "Y" chord, and corrective actions if necessary. This new AD adds various inspections for discrepancies at the aft pressure bulkhead, and related investigative and corrective actions if necessary. This AD was prompted by several reports of fatigue cracking at that location. We are issuing this AD to detect and correct such fatigue cracking, which could result in rapid decompression of the fuselage.
This paragraph restates the initial inspection required by paragraph (a) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999). Perform either inspection specified by paragraph (g)(1) or (g)(2) of this AD at the time specified in paragraph (h) of this AD.
(1) Perform a low frequency eddy current (LFEC) inspection from the aft side of the aft pressure bulkhead to detect discrepancies (including cracking, misdrilled fastener holes, and corrosion) of the web of the upper section of the aft pressure bulkhead at body station 1016 at the aft fastener row attachment to the “Y” chord, from stringer 15 left (S-15L) to stringer 15 right (S-15R), in accordance with Boeing 737 Nondestructive Test Manual D6-37239, Part 6, Section 53-10-54, dated December 5, 1998.
(2) Perform a detailed visual inspection of the aft fastener row attachment to the “Y” chord from the forward side of the aft pressure bulkhead to detect discrepancies (including cracking, misdrilled fastener holes, and corrosion) of the entire web of the aft pressure bulkhead at body station 1016.
This paragraph restates the compliance times specified in paragraph (b) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999). Perform the inspection required by paragraph (g) of this AD at the time specified in paragraph (h)(1), (h)(2), or (h)(3) of this AD, as applicable.
(1) For airplanes that have accumulated 40,000 or more total flight cycles as of May 10, 1999 (the effective date of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999)): Inspect within 375 flight cycles or 60 days after May 10, 1999 (the effective date of AD 99-08-23), whichever occurs later.
(2) For airplanes that have accumulated 25,000 or more total flight cycles and fewer than 40,000 total flight cycles as of May 10, 1999 (the effective date of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999)): Inspect within 750 flight cycles or 90 days after May 10, 1999 (the effective date of AD 99-08-23), whichever occurs later.
(3) For airplanes that have accumulated fewer than 25,000 total flight cycles as of May 10, 1999 (the effective date of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999)): Inspect prior to the accumulation of 25,750 total flight cycles.
This paragraph restates the repetitive inspections required by paragraph (c) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999). Within 1,200 flight cycles after performing the initial inspection required by paragraph (g) of this AD, and thereafter at intervals not to exceed 1,200 flight cycles: Perform either inspection specified by paragraph (g)(1) or (g)(2) of this AD.
This paragraph restates the corrective actions required by paragraph (d) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999). If any discrepancy is detected during any inspection required by paragraph (g), (h), or (i) of this AD: Prior to further flight, accomplish the actions specified by paragraphs (j)(1) and (j)(3) of this AD, and paragraph (j)(2) of this AD, if applicable.
(1) Perform a high frequency eddy current inspection from the forward side of the bulkhead to detect cracking of the web at the “Y” chord attachment, around the entire periphery of the “Y” chord, in accordance with Boeing 737 Nondestructive Test Manual D6-37239, Part 6, Section 51-00-00, Figure 23, dated November 5, 1995.
(2) If the most recent inspection performed in accordance with paragraph (g) of this AD was not a detailed visual inspection: Accomplish the actions specified by paragraph (g)(2) of this AD. If the inspection was a detailed visual inspection, it is not necessary to repeat that inspection prior to further flight.
(3) Repair any discrepancy such as cracking or corrosion or misdrilled fastener holes using a method approved in accordance with the procedures specified in paragraph (u) of this AD.
At the later of the times specified in paragraphs (k)(1) and (k)(2) of this AD: Do detailed and LFEC inspections of the aft side of the bulkhead web, or do detailed and HFEC inspections from the forward side of the bulkhead, and do all applicable related investigative and corrective actions; in accordance with Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraphs (r)(1) and (r)(3) of this AD. Inspect for cracks, incorrectly drilled fastener holes, and elongated fastener holes. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections at the applicable times specified in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
(1) Prior to the accumulation of 25,000 total flight cycles.
(2) Except as required by paragraphs (r)(2) and (r)(4) of this AD, at the later of the times specified in the “Compliance Time” column in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
Except as required by paragraphs (r)(2) and (r)(5) of this AD, at the applicable time specified in table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: Do detailed and eddy current inspections of the web from the forward or aft side of the bulkhead for cracks, incorrectly drilled fasteners, and elongated fasteners, in accordance with Part III of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraphs (r)(1) and (r)(3) of this AD. If any crack, incorrectly drilled fastener, elongated fastener, or corrosion is found, before further flight, repair the web using a method approved in accordance with the procedures specified in paragraph (u) of this AD. Repeat the inspections at the applicable times specified in table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
Except as required by paragraphs (r)(2) and (r)(5) of this AD, at the applicable time specified in table 3 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: Do a one-time LFEC inspection for cracks on the aft side of the bulkhead of the web located under the outer circumferential tear strap, or do a one-time HFEC inspection for cracks from the forward side of the bulkhead of the web located under the outer circumferential tear strap, in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraph (r)(1) of this AD. If any cracking is found, before further flight, repair the bulkhead using a method approved in accordance with the procedures specified in paragraph (u) of this AD.
Except as required by paragraph (r)(2) of this AD, at the applicable time specified in table 4 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: Do a detailed inspection from the aft side of the bulkhead for oil-canning and do all applicable related investigative and corrective actions, in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraph (r)(1) of this AD. Do all related investigative and corrective actions before further flight. Thereafter, repeat the inspection at the applicable times specified in table 4 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011. For oil-cans found within the limits specified in Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: In lieu of installing the repair before further flight, at the applicable times specified in table 4 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, do initial and repetitive detailed and HFEC inspections for cracks of the oil-canning and install the repair, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011. If any crack is found, before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (u) of this AD. Installing the repair terminates the repetitive inspections for cracks.
Except as required by paragraphs (r)(2) and (r)(5) of this AD, at the applicable time specified in table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: Do an eddy current inspection to detect any cracking of the dome cap at the center of the bulkhead, and do all applicable corrective actions, in accordance with Part IV of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011. Do all corrective actions before further flight. Repeat the inspection at the times specified in table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
Except as required by paragraphs (r)(2) and (r)(5) of this AD, at the applicable time specified in table 6 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: Do an HFEC inspection to detect any cracking of the “Z” stiffener flanges at the dome cap in the center of the bulkhead, in accordance with Part V of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraph (r)(1) of this AD. If any crack is found, before further flight, repair the flanges using a method approved in accordance with the procedures specified in paragraph (u) of this AD. Repeat the inspection at the applicable times specified in table 6 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
Except as required by paragraph (r)(2) of this AD, at the applicable time specified in table 7 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: Do a detailed inspection of the bulkhead web and stiffeners for existing repairs, in accordance with Part VI of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraph (r)(1) of this AD.
(1) If any repair identified in the “Condition” column of table 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, is found and the “Reference” column refers to Appendix A, B, C, or D of that service bulletin: At the applicable times specified in table 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraph (r)(2) of this AD, do a HFEC inspection or a LFEC inspection of the web for cracking, in accordance with Appendix A, B, C, or D, as applicable, of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011. If any cracking is found, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (u) of this AD. Repeat the inspections, thereafter, at the applicable intervals specified in table 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
(2) If any repair identified in the “Condition” column of table 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, is found and the “Reference” column refers to Appendix E of that service bulletin: At the applicable times specified in table 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as required by paragraph (r)(2) of this AD, remove the repair and replace with a new repair, in accordance with Appendix E of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
(3) If any non-SRM (structural repair manual) repair is found and the repair does not have FAA-approved damage tolerance inspections, except as required by paragraph (r)(2) of this AD, at the applicable time specified in table 7 of Paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011: Contact the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle Aircraft Certification Office, for damage tolerance inspections. Do those damage tolerance inspections at the times given using a method approved in accordance with the procedures specified in paragraph (u) of this AD.
(1) Where Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (u) of this AD.
(2) Where Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, specifies a compliance time “after the date of Revision 1 to this service bulletin,” “from the date of Revision 3 of this service bulletin,” “after the date of Revision 3 to this service bulletin,” or “of the effective date of AD 99-08-23,” this AD requires compliance within the specified compliance time after the effective date of this AD.
(3) Access and restoration procedures specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, are not required by this AD. Operators may do those procedures following their maintenance practices.
(4) Where table 1 of paragraph 1.E., “Compliance” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, specifies a compliance time relative to actions done “in accordance with paragraph (a)(2) of AD 99-08-23,” this AD requires compliance within the specified compliance time relative to actions specified in paragraph (g)(2) of this AD.
(5) Where the Condition columns in tables 2, 3, 5, and 6 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011, refer to total flight cycles, this AD applies to the airplanes with the specified total flight cycles as of the effective date of this AD.
Accomplishment of the requirements of paragraphs (k) through (q) of this AD terminates the requirements of paragraphs (g) through (j) of this AD.
