Airworthiness Directive · Amendment 39-14503 · Boeing Model 747 Airplanes
Boeing Model 747 Airplanes
Superseded. A later AD replaced this one: AD 2010-14-07. Comply with the one in force.
This AD applies to Boeing 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; line numbers 1 through 1307 inclusive.
The FAA is superseding three existing airworthiness directives (ADs) that apply to certain Boeing Model 747 airplanes. The existing ADs currently require repetitive inspections of the body station (BS) 2598 bulkhead, and corrective action if necessary. This new AD adds a requirement to modify the bulkhead, including a one-time inspection and corrective action if necessary, which terminates certain repetitive inspections. This AD also requires a post-modification inspection of the modified area. This AD results from new reports of cracking in all three areas that require inspection in accordance with the existing ADs. We are issuing this AD to prevent fatigue cracking of the BS 2598 bulkhead structure, which could result in inability of the structure to carry horizontal stabilizer flight loads, and loss of controllability of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Before the accumulation of 10,000 total flight cycles, or within 1,000 flight cycles after August 16, 2001 (the effective date of AD 2001-14-07), whichever occurs later: Do an open-hole HFEC inspection to find cracking of the bulkhead frame support under the hinge support fittings of the horizontal stabilizer on the left and right sides at BS 2598, in accordance with Figure 2 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2449, Revision 1, dated May 24, 2001; or Revision 2, dated March 14, 2002. Repeat the inspection after that at intervals not to exceed 3,000 flight cycles. Inspections accomplished before August 16, 2001, per Boeing Alert Service Bulletin 747-53A2449, dated June 8, 2000, are considered acceptable for compliance with the applicable inspection specified in this paragraph.
If any cracking is found during any inspection required by paragraph (f) of this AD, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, or using a method approved in accordance with paragraph (n) of this AD.
Do a surface HFEC inspection of the forward and aft inner chords, the frame support, and the splice fitting of the forward inner chord of the upper corner of the station 2598 bulkhead to find cracking, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 2, dated October 5, 2000; or Revision 3, dated September 27, 2001; at the latest of the times specified in paragraphs (h)(1) and (h)(2) of this AD, as applicable. Repeat the inspection after that at intervals not to exceed 1,500 flight cycles.
(1) For airplanes having line numbers 1 through 1241 inclusive:
(i) Before the accumulation of 6,000 total flight cycles.
(ii) Within 500 flight cycles after August 28, 2001 (the effective date of AD 2001-15-03).
(iii) For airplanes inspected before August 28, 2001, in accordance with Boeing Alert Service Bulletin 747-53A2427, dated December 17, 1998 (including inspections of the splice fitting), or Revision 1, dated October 28, 1999: Within 1,500 flight cycles after accomplishment of the last inspection done in accordance with the original service bulletin or Revision 1, as applicable.
(2) For airplanes having line numbers 1242 through 1307 inclusive:
(i) Before the accumulation of 16,000 total flight cycles.
(ii) Within 500 flight cycles after August 28, 2001.
(iii) For airplanes inspected before August 28, 2001, in accordance with Boeing Alert Service Bulletin 747-53A2427, dated December 17, 1998 (including inspections of the splice fitting), or Revision 1, dated October 28, 1999: Within 1,500 flight cycles after accomplishment of the last inspection done in accordance with the original service bulletin or Revision 1, as applicable.
(i) If any cracking is found during the inspections required by paragraph (h) of this AD, before further flight, repair in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 2, dated October 5, 2000; or Revision 3, dated September 27, 2001; except where the alert service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, before further flight, repair in accordance with a method approved by the Manager, Seattle ACO, or using a method approved in accordance with the procedures specified in paragraph (n) of this AD.
Before the accumulation of 10,000 total flight cycles, or within 1,000 flight cycles after October 27, 2003 (the effective date of AD 2003-19-08), whichever is later: Do a detailed inspection of the body station 2598 bulkhead for discrepancies (cracking, elongated fastener holes) of the areas specified in paragraphs (j)(1) and (j)(2) of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2467, dated July 26, 2001; or Revision 1, dated April 28, 2005. Repeat the inspections after that at intervals not to exceed 3,000 flight cycles.
(1) The lower aft inner chords.
(2) The upper aft outer chords, and the diagonal brace attachment fittings, flanges, and rods.
Note 1: For the purposes of this AD, a detailed inspection is “an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required.”
If any discrepancy is found during any inspection required by paragraph (j) of this AD: Before further flight, repair in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2467, dated July 26, 2001; or Revision 1, dated April 28, 2005. If the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair in accordance with a method approved by the Manager, Seattle ACO, or using a method approved in accordance with the procedures specified in paragraph (n) of this AD.
Before the accumulation of 20,000 total flight cycles, or within 48 months after the effective date of this AD, whichever occurs later: Modify the bulkhead by doing all applicable actions including surface and open-hole HFEC inspections for cracking of the upper forward inner chord, aft inner chord, upper splice fitting, and frame support fitting, as specified in the Accomplishment Instructions of Boeing Service Bulletin 747-53-2473, dated March 24, 2005. Repair any cracks before further flight in accordance with the service bulletin. Where the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions: Before further flight, repair the cracks using a method approved in accordance with the procedures specified in paragraph (n) of this AD. Accomplishment of the modification terminates the repetitive inspections required by paragraphs (f), (h), and (j)(1) of this AD.
Within 20,000 flight cycles after the modification required by paragraph (l) of this AD, inspect the BS 2598 bulkhead for cracks, and repair any cracks before further flight, in accordance with a method approved by the Manager, Seattle ACO.
