Airworthiness Directive · Amendment 39-17572 · Fuselage
The Boeing Company Airplanes
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, and 747SR series airplanes, certificated in any category, having line numbers 1 through 1419 inclusive; except for Model 747-400 series airplanes that have been modified into the Model 747-400 large cargo freighter configuration.
We are superseding airworthiness directive (AD) 2010-20-08, which applied to certain 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, and 747SR series airplanes. AD 2010-20-08 required repetitive inspections to find cracking of the web, strap, inner chords, inner chord angle of the forward edge frame of the number 5 main entry door cutouts; the frame segment between stringers 16 and 31; repair if necessary; and repetitive inspections for cracking of repairs. This new AD expands the previous fuselage areas that are inspected for cracking. This AD was prompted by multiple reports of cracking outside of the previous inspection areas and a report of a crack that initiated at the aft edge of the inner chord rather than initiating at a fastener location. We are issuing this AD to detect and correct such cracks, which could cause damage to the adjacent body structure and could result in depressurization of the airplane in flight.
This paragraph restates the requirements of paragraph (g) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010). For airplanes having line numbers 1 through 1304 inclusive: Inspect the airplane for cracks between stringers 23 and 31 per Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001; or Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009; at the later of the applicable times specified in paragraph (h) or (i) of this AD, per table 1 to paragraphs (g) and (h) of this AD. Where there are differences between the AD and Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001; or Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009; the AD prevails.
| Type of Inspection | Area to Inspect |
|---|---|
| (1) Detailed Visual | Strap inner chords forward and aft of the web, and exposed web adjacent to the inner chords on station 2231 frame from stringers 23 through 31 per Figure 5 or Figure 6 of the service bulletins specified in paragraph (g) or (h) of this AD, as applicable. |
| (2) Surface High Frequency Eddy Current (HFEC) | Station 2231 inner chord angles at lower main sill interface per Figure 5 or Figure 6 of the service bulletins specified in paragraph (g) or (h) of this AD, as applicable. |
| (3) Open Hole HFEC | Station 2231 frame fastener locations per Figures 4 and 7, and either Figure 5 or 6 of the service bulletins specified in paragraph (g) or (h) of this AD, as applicable. |
| (4) Surface HFEC | Around fastener locations on station 2231 inner chords from stringers 23 through 31 per Figure 5 or Figure 6 of the service bulletins specified in paragraph (g) or (h) of this AD, as applicable. |
| (5) Low Frequency Eddy Current (LFEC) | Station 2231 frame strap in areas covered by the reveal per Figure 5 or Figure 6 of the service bulletins specified in paragraph (g) or (h) of this AD, as applicable. |
Note 1 to paragraph (g) of this AD: There is no terminating action currently available for the inspections required by paragraph (g) of this AD.
This paragraph restates the requirements of paragraph (h) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010). Do the inspections specified in paragraph (g) of this AD at the applicable times specified in paragraph (h)(1) or (h)(2) of this AD. Repeat the inspections at intervals not to exceed 3,000 flight cycles until the inspections required by paragraph (m) or (o) of this AD are done. Where there are differences between the AD and Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001; or Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009; the AD prevails.
(1) Do the inspections per table 1 to paragraphs (g) and (h) of this AD at the applicable time specified in the logic diagram in Figure 1 of Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001. Where the compliance time in the logic diagram specifies a compliance time beginning “from receipt of this service bulletin,” this AD requires that the compliance time begin “after September 12, 2001 (the effective date of AD 2001-16-02, Amendment 39-12370 (66 FR 41440, August 8, 2001)).”
(2) After November 9, 2010 (the effective date of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010)), do the inspections per table 1 to paragraphs (g) and (h) of this AD at the applicable compliance time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. Where the compliance time in Boeing Alert Service Bulletin 747-53A2450, Revision 2, including Appendix A, dated January 4, 2001, specifies a compliance time beginning “after the date on Revision 2 of this service bulletin,” this AD requires that the compliance time begin “after September 12, 2001 (the effective date of AD 2001-16-02, Amendment 39-12370 (66 FR 41440, August 8, 2001)).”
This paragraph restates the requirements of paragraph (i) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010). Within 3,000 flight cycles after accomplishment of the inspections specified in Figure 1 of Boeing Alert Service Bulletin 747-53A2450, dated May 4, 2000; or Boeing Alert Service Bulletin 747-53A2450, Revision 1, dated July 6, 2000; repeat the inspections specified in paragraph (g) of this AD at intervals not to exceed 3,000 flight cycles until the inspections required by paragraph (m) or (o) of this AD are done. Where there are differences between the AD and Boeing Alert Service Bulletin 747-53A2450, Revision 2, dated January 4, 2001; or Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009; the AD prevails.
This paragraph restates the requirements of paragraph (j) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010).
(1) For all airplanes: Before the accumulation of 16,000 total flight cycles, or within 1,500 flight cycles after November 9, 2010 (the effective date of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010)), whichever occurs later, do a detailed inspection, an open hole HFEC inspection, a surface HFEC inspection, and a subsurface LFEC inspection for cracking of the forward edge frame of the number 5 main entry door cutouts, at station 2231, between stringers 16 and 23; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. Repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles.
(2) The part number of the nut for fastener code “K” in Figure 7 of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009, should be “BACN10JC3CD,” instead of “BACB30JC3CD.” In addition, the part number of the optional nut for this fastener code should be “BACN10YR3CD,” instead of “BACN10YR4CD,” in Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009.
This paragraph restates the requirements of paragraph (k) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010). For airplanes having line numbers 1305 and on: Before the accumulation of 16,000 total flight cycles, or within 1,500 flight cycles after November 9, 2010 (the effective date of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010)), whichever occurs later, do a detailed inspection, an open hole HFEC inspection, a surface HFEC inspection, and a subsurface LFEC inspection for cracking of the forward edge frame of the number 5 main entry door cutouts, at station 2231, between stringers 23 and 31; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. Repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles.
This paragraph restates the requirements of paragraph (l) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010). If any crack is found during any inspection required by paragraph (g), (j), or (k) of this AD, before further flight, repair the crack in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, in accordance with data meeting the type certification basis of the airplane approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make those findings; or in accordance with Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009; as applicable. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD. As of November 9, 2010 (the effective date of AD 2010-20-08), repair the crack using a method approved in accordance with the procedures specified in paragraph (s) of this AD.
This paragraph restates the requirements of paragraph (m) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010). Except as required by paragraph (n) of this AD, for airplanes on which the forward edge frame of the number 5 main entry door cutouts, at station 2231, between stringers 16 and 31, is repaired as specified in Boeing Alert Service Bulletin 747-53A2450: Within 3,000 flight cycles after doing the repair, or within 1,500 flight cycles after November 9, 2010 (the effective date of AD 2010-20-08), whichever occurs later, do the detailed, LFEC, and HFEC inspections of the repaired area for cracks, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009. If no cracking is found, repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles. If any crack is found: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (s) of this AD. Doing the inspections specified in paragraph (m) of this AD terminates the repetitive inspections required by paragraphs (g), (h), (i), (j), and (k) of this AD for the repaired area.
This paragraph restates the requirements of paragraph (n) of AD 2010-20-08, Amendment 39-16442 (75 FR 61337, October 5, 2010). For any frame that is repaired in accordance with a method other than the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 5, dated January 29, 2009: Do the inspection in accordance with a method approved in accordance with the procedures specified in paragraph (s) of this AD.
Before the accumulation of 16,000 total flight cycles, or within 3,000 flight cycles after the effective date of this AD, whichever occurs later, do the inspections required by paragraphs (o)(1) through (o)(5) of this AD, except as specified in paragraph (p) of this AD. Do all actions required by this paragraph in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 7, dated November 2, 2011. Repeat the inspections thereafter at the applicable times specified in Paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2450, Revision 7, dated November 2, 2011. Accomplishment of the initial inspections required by this paragraph terminates the requirements of paragraphs (g) through (k) of this AD.
(1) Do a detailed inspection for cracking on the frame strap, inner chords forward and aft of the web, and exposed web adjacent to the inner chords from stringer 15 to 31.
(2) Do an HFEC inspection of the station 2231 frame fastener locations for cracking from stringer 16 to 31, including locations common to the upper main sill strap and stringer clip at stringer 16.
(3) Do an HFEC inspection for cracking of the frame inner chords around the fastener heads from stringer 15 to 31.
(4) Do an HFEC inspection for cracking of the aft edge of the aft inner chord, of the forward edge of the forward inner chord, and of the forward and aft edges of the frame strap from stringer 15 to 31.
(5) Do an LFEC inspection for cracking of the station 2231 frame strap from stringer 16 to 31 in areas covered by the reveal.
For airplanes on which the post-repair inspections are being done as specified in paragraph (m) of this AD: For the repaired area only, continue the inspections as specified in paragraph (m) of this AD in lieu of the inspections specified in paragraph (o) of this AD.
(1) If any cracking is found during any inspection required by paragraph (o) of this AD: Before further flight, repair the cracking, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 7, dated November 2, 2011.
(2) If any cracking is found during any inspection required by paragraph (p) or (r) of this AD: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (s) of this AD.
(1) For any airplane repaired as specified in paragraph (q)(1) of this AD: Within 3,000 flight cycles after doing the repair, do detailed, LFEC, and HFEC inspections of the repaired area for cracking, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2450, Revision 7, dated November 2, 2011. If no cracking is found, repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles. If any cracking is found: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (s) of this AD.
(2) For any airplane repaired as specified in paragraph (q)(2) of this AD: Before further flight, contact the Manager, Seattle Aircraft Certification Office (ACO), FAA, for instructions and compliance times for doing an inspection of the repaired area for cracking. Do the inspection at the compliance times specified using the inspection procedures provided. If any cracking is found: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (s) of this AD.
