Airworthiness Directive · Amendment 39-15812 · 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
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
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, except those that have been converted to a Model 747-400 LCF configuration.
The FAA is superseding an existing airworthiness directive (AD), which applies to all Boeing Model 747 series airplanes. That AD currently requires repetitive detailed inspections of the aft pressure bulkhead for indications of "oil cans" and previous oil can repairs, and corrective actions if necessary. An oil can is an area on a pressure dome web that moves when pushed from the forward side. This new AD requires a reduced compliance time for the initial detailed inspection and revises the applicability. This AD results from a report that cracks in oil-canned areas were found during an inspection of the aft pressure bulkhead. We are issuing this AD to detect and correct the propagation of fatigue cracks in the vicinity of oil cans on the web of the aft pressure bulkhead, which could result in rapid decompression of the airplane and overpressurization of the tail section, and consequent loss of control 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.
Note 1: This AD refers to certain portions of Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; and Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008; for inspections and repair information. In addition, this AD specifies requirements beyond those included in Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; and Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008. Where the AD and Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; and Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008; differ, the AD prevails.
At the earlier of the times specified in paragraphs (f)(1) and (f)(2) of this AD, perform a detailed inspection of the aft pressure bulkhead for indications of oil cans and previous oil can repairs, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008. After the effective date of this AD, Revision 1 must be used.
(1) Prior to the accumulation of 30,000 total flight cycles, or within 1,000 flight cycles after September 13, 2004 (the effective date of AD 2004-16-09), whichever is later.
(2) Prior to the accumulation of 20,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later.
Note 2: 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.”
(g) If no indication of an oil can is found and no indication of a previous oil can repair is found during the detailed inspection required by paragraph (f) of this AD, repeat the detailed inspection thereafter at intervals not to exceed 2,000 flight cycles.
If any indication of an oil can is found during the detailed inspection required by paragraph (f) or (g) of this AD, before further flight, perform an eddy current inspection of the web around the periphery of the oil can indication for cracks, as shown in Figure 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008. After the effective date of this AD, Revision 1 must be used.
(i) If no crack is found during the eddy current inspection required by paragraph (i) of this AD, do the actions specified in paragraph (i)(1) or (i)(2) of this AD, as applicable.
(1) For the oil can that meets the allowable limits specified in Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008: Repeat the eddy current inspection specified in paragraph (h) of this AD thereafter at intervals not to exceed 1,000 flight cycles. As an option, repair the oil can in accordance with paragraph (i)(2) of this AD.
(2) For the oil can that does not meet the allowable limits specified in Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008: Before further flight, repair the oil can in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008. After the effective date of this AD, Revision 1 must be used. If the repair eliminates the oil can, accomplishment of this repair constitutes terminating action for the repetitive eddy current inspection requirements of paragraph (i)(1) of this AD for that location only. However, the repetitive detailed inspection required by paragraph (g) of this AD is still required. If any oil can remains after the repair, repeat the eddy current inspection specified in paragraph (h) of this AD thereafter at intervals not to exceed 1,000 flight cycles.
If any previous oil can repair is found during the detailed inspection required by paragraph (f) or (g) of this AD, before further flight, do a detailed inspection of the web for cracks and oil cans, as shown in Figure 4 or Figure 5, as applicable, of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008. After the effective date of this AD, Revision 1 must be used.
(1) If no crack and no oil can are found, repeat the detailed inspection in accordance with paragraph (f) of this AD.
(2) If any oil can is found, before further flight, do the eddy current inspection for cracks, as shown in Figure 3 of Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008. After the effective date of this AD, Revision 1 must be used. If no crack is found during the eddy current inspection required by this paragraph, do the actions specified in paragraph (i)(1) or (i)(2) of this AD, as applicable, at the time specified in the applicable paragraph.
If any crack is found during any inspection required by this AD, before further flight, repair in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008. After the effective date of this AD, Revision 1 must be used. If any crack or damage exceeds limits specified in Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008; and Boeing Alert Service Bulletin 747-53A2482, dated October 3, 2002; or Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008; specifies to contact Boeing for appropriate action: Before further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings; or using a method approved in accordance with the procedures specified in paragraph (m) of this AD. For a repair method to be approved, the approval must specifically reference this AD.
As of the effective date of this AD, if any crack or damage is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2482, Revision 1, dated February 21, 2008, specifies to contact Boeing for appropriate action (repair data): Before further flight, repair the crack or damage using a method approved in accordance with the procedures specified in paragraph (m) of this AD.
