Airworthiness Directive · Amendment 39-17815 · Fuselage
the Boeing Company Airplanes
Superseded. A later AD replaced this one: AD 2014-14-03. Comply with the one in force.
This AD applies to The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747 airplanes. This AD was prompted by reports of cracking in particular areas of the bulkhead structure at body station (BS) 2598. This AD requires repetitive inspections, including post-repair and post-modification inspections, for cracking in the bulkhead structure at BS 2598; certain one-time inspections of certain fasteners and support frame modifications on certain airplanes; related investigative and corrective actions, if necessary; and an interim modification that would terminate certain repetitive inspections. We are issuing this AD to detect and correct fatigue cracking of the BS 2598 bulkhead structure, which could adversely affect the structural integrity of the bulkhead and the horizontal stabilizer support structure, and result in loss of controllability of the airplane.
For airplanes on which the bulkhead (support frame) modification specified in Boeing Service Bulletin 747-53A2473 or Boeing Alert Service Bulletin 747-53A2837 has not been done, and on which an interim modification or aft inner chord repair specified in Boeing Alert Service Bulletin 747-53A2427 has not been done: At the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, except as provided by paragraph (m)(1), (m)(2), or (m)(3) of this AD, as applicable, do an open-hole and surface high frequency eddy current (HFEC) inspection for cracking in the bulkhead (support frame), which includes the bulkhead splice fitting, frame supports, forward and aft inner chords, floor supports, and upper and lower web panels; do a surface HFEC inspection for cracking in the bulkhead upper web assembly; do an open-hole and surface HFEC inspection for cracking in the bulkhead lower web assembly; and do all applicable corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, except as required by paragraphs (h), (m)(4), (m)(5), and (m)(6) of this AD. Do all applicable corrective actions before further flight. Repeat the applicable inspections, thereafter, at the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013. Doing the modification required by paragraph (j) of this AD terminates the repetitive inspections required by this paragraph.
For airplanes in Groups 1 and 2, as identified in Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, on which no cracking was found during any inspection required by paragraph (g) of this AD: At the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, except as provided by paragraph (m)(2) of this AD, do the interim modification, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013. Doing the interim modification terminates the repetitive inspections required by paragraph (g) of this AD in the area of the modification only. The repetitive inspections of the bulkhead lower web, as specified in paragraph (g) of this AD, must be done. If the aft inner chord repair or upper web repair specified in Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, has been accomplished, an interim modification on the side of the airplane that has the repair is not required by this paragraph.
For airplanes on which an interim modification, aft inner chord repair, or upper web repair has been done, as specified in paragraph (g) or (h) of this AD: At the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, except as specified in paragraph (m)(1), (m)(2), or (m)(3) of this AD, as applicable, do the actions specified in paragraphs (i)(1) and (i)(2) of this AD, and all applicable corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, except as required by paragraph (m)(4) of this AD. Do all applicable corrective actions before further flight. Repeat the inspections thereafter at the applicable intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013. Doing the modification required by paragraph (j) of this AD terminates the repetitive inspections required by this paragraph.
(1) Do forward side surface HFEC inspections for cracking of the bulkhead forward inner chord, splice fitting, and frame support.
(2) Do surface and open-hole HFEC inspections for cracking in the repaired and modified areas of the bulkhead, as applicable.
For airplanes on which the bulkhead (support frame) modification, as specified in Boeing Service Bulletin 747-53A2473 has not been done as of the effective date of this AD: At the applicable time specified in tables 2 and 3 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, do the bulkhead (support frame) modification and inspections and all applicable related investigative and corrective actions; in accordance with steps 3.B.3., 3.B.4., and 3.B.5. of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, except as required by paragraph (m)(4) of this AD. Do all applicable related investigative and corrective actions before further flight. Doing the modification in this paragraph terminates the inspections required by paragraphs (g) and (i) of this AD.
(1) For airplanes on which the bulkhead (support frame) modification, as specified in Boeing Service Bulletin 747-53A2473 has been done: Except as provided by paragraphs (m)(7) and (m)(8) of this AD, at the applicable time specified in tables 6, 7, 8, and 9 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, do support frame post-modification inspections, and open-hole HFEC inspections for cracking in the hinge support, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, except as required by paragraph (m)(4) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections thereafter at the applicable times specified in tables 6, 7, 8, and 9 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011.
(2) For airplanes on which the support frame modification, as specified in Boeing Service Bulletin 747-53A2473, Revision 1, dated February 20, 2007 (which is not incorporated by reference in this AD), has been done: Except as specified in paragraphs (m)(7) and (m)(8) of this AD, at the applicable time specified in tables 4 and 5 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, do a one-time general visual inspection of the frame web and upper shear deck (floor support) chord aft side for fasteners that were installed as part of an inner chord repair removal; and a one-time general visual inspection of the upper forward inner chord, frame support fitting, and splice fitting for the installation of certain fasteners; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, except as required by paragraph (m)(4) of this AD. Do all applicable related investigative and corrective actions at the applicable times specified in tables 4 and 5 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011.
(3) For airplanes on which the support frame modification, as specified in Boeing Service Bulletin 747-53A2473, dated March 24, 2005 (which was incorporated by reference in AD 2006-05-06, Amendment 39-14503 (71 FR 12125, March 9, 2006)), has been done: Except as specified in paragraphs (m)(7) and (m)(8) of this AD, at the applicable time specified in tables 5 and 10 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, do a one-time general visual inspection of the upper forward inner chord, frame support fitting, and splice fitting for the installation of certain fasteners; a one-time general visual inspection for any repair installed on the left and right side of the aft inner chord; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, except as required by paragraph (m)(4) of this AD. Do all applicable related investigative and corrective actions at the applicable times specified in tables 5 and 10 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011.
(4) For airplanes on which a post-modification inspection was done using paragraph 3.B.8. of Part 1 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 3, dated July 14, 2011 (which is not incorporated by reference in this AD): Except as required by paragraphs (m)(7) and (m)(8) of this AD, at the applicable time in table 11 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, do a one-time surface HFEC inspection of the support frame outer chord for cracking, in accordance with Part 1 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011. If any cracking is found, repair before further flight, using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
For airplanes on which cracking was found during a post-modification inspection and was repaired by doing the installation of an upper or lower corner post-modification web crack repair, as specified in Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011: At the applicable times specified in tables 6 and 8 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, do a bulkhead (support frame) post-repair inspection, and do all applicable corrective actions, in accordance with paragraph a., b., or c. of Part 4 of paragraph 3.B.8 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, as applicable, except as required by paragraph (m)(4) of this AD. Repeat the inspection, thereafter, at the applicable times specified in tables 6 and 8 of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011.
(1) Where Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, specifies a compliance time after “the date on Revision 2 of this service bulletin,” this AD requires compliance within the specified compliance time after August 28, 2001 (the effective date of AD 2001-15-03, Amendment 39-12337 (66 FR 38365, July 24, 2001)).
(2) Where Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, specifies a compliance time after “the date on Revision 4 of this service bulletin,” this AD requires compliance within the specified compliance time after August 5, 2010 (the effective date of AD 2010-14-07, Amendment 39-16352 (75 FR 38001, July 1, 2010)).
(3) Where Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, specifies a compliance time “after the date on the respective service bulletin revision” this AD requires compliance within the specified compliance time after the effective date of this AD.
(4) If any cracking is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013; or Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011; 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 (q) of this AD.
(5) If, during any inspection required by paragraph (g) of this AD, any cracking is found in the bonded web doubler, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
(6) Where Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, specifies accomplishing inspections for cracking in the forward and aft inner chords, splice fittings, floor supports, and upper and lower web panels, this AD also requires doing an open-hole HFEC inspection of the bonded web doubler if present.
(7) Where Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, specifies a compliance time “after the date on Revision 2 of this service bulletin,” this AD requires compliance within the specified compliance time as of August 5, 2010 (the effective date of AD 2010-14-07, Amendment 39-16352 (75 FR 38001, July 1, 2010)).
(8) Where Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, specifies a compliance time “after the date on Revision 3 of this service bulletin,” or “after the date on Revision 4 of this service bulletin,” this AD requires compliance within the specified compliance time “after the effective date of this AD.”
Accomplishing the modification of the bulkhead at BS 2598 in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2837, dated July 13, 2012, terminates the requirements of paragraphs (g), (h), (i), (j), (k), and (l) of this AD, except where Boeing Alert Service Bulletin 747-53A2837, dated July 13, 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 (q) of this AD.
(1) Accomplishing the inspections, repairs, and modification in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2473, Revision 4, dated December 1, 2011, is an acceptable terminating action for the corresponding inspections, repairs, and modification at the BS 2598 support frame required by paragraphs (i), (j), (k), (1), (m), (n), (o), (p), (q), (r), (s), (t), (u), and (v) of AD 2010-14-07, Amendment 39-16352 (75 FR 38001, July 1, 2010). Where Boeing Service Bulletin 747- 53A2473, Revision 4, dated December 1, 2011, specifies to contact Boeing for repair instructions, the repair instructions must be approved in accordance with the procedures specified in paragraph (q) of this AD. All provisions of AD 2010-14-07 that are not specifically referenced in this paragraph remain fully applicable and must be complied with.
(2) Accomplishing the inspections, repairs, and interim modification in accordance with Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, is an acceptable terminating action for the corresponding inspections, repairs and interim modification at the BS 2598 bulkhead required by paragraphs (i), (j), (o), (s), (t), (u), and (v) of AD 2010-14-07, Amendment 39-16352 (75 FR 38001, July 1, 2010). Where Boeing Alert Service Bulletin 747-53A2427, Revision 7, dated July 19, 2013, specifies to contact Boeing for repair data, the repair data must be approved in accordance with the procedures specified in paragraph (q) of this AD. All provisions of AD 2010-14-07 that are not specifically referenced in this paragraph remain fully applicable and must be complied with.
