Airworthiness Directive · Amendment 39-14326 · Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR Series Airplanes
Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR Series Airplanes
This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR series airplanes; certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747- 300, 747SP, and 747SR series airplanes. This AD requires repetitive inspections to detect cracks in various areas of the upper deck floor beams, and repair if necessary. This AD results from fatigue testing that revealed severed upper chords of the upper deck floor beams due to fatigue cracking. We are issuing this AD to detect and correct cracking in the upper chords of the upper deck floor beams. Undetected cracking could result in large deflection or deformation of the upper deck floor beams, resulting in damage to wire bundles and control cables for the flight control system, and reduced controllability of the airplane. Multiple adjacent severed floor beams could result in rapid decompression 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: Paragraphs (f) and (g) of this AD restate the requirements of paragraphs (a) and (c) of AD 2002-10-10. As allowed by the phrase, “unless accomplished previously,” if those requirements of AD 2002-10-10 have already been accomplished, this AD does not require that those actions be repeated.
Before the accumulation of 22,000 total flight cycles, or within 1,000 flight cycles after June 11, 1993 (the effective date of AD 93-08-12, amendment 39-8559), whichever occurs later, unless accomplished previously within the last 2,000 flight cycles; and thereafter at intervals not to exceed 3,000 flight cycles: Do a detailed inspection to detect cracks in the upper deck floor beams in Sections 41 and 42, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53-2349, dated June 27, 1991; Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000; or Boeing Service Bulletin 747-53A2349, Revision 2, dated April 3, 2003. After the effective date of this AD, only Boeing Service Bulletin 747-53A2349, Revision 2, dated April 3, 2003, may be used. Continue doing the inspections required by this paragraph until the inspections required by paragraph (h) or (l) of this AD are accomplished.
Before further flight, repair any cracking detected during the inspections done in accordance with paragraph (f) of this AD, according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to data meeting the certification basis of the airplane approved a Boeing Company Designated Engineering Representative (DER) who has been authorized by the Manager, Seattle ACO, to make such findings; or according to a method approved in accordance with the procedures specified in paragraph (s) of this AD.
Note 2: Paragraphs (h), (i), (j), and (k), of this AD restate the requirements of paragraphs (d), (e), (f), and (g), of AD 2002-10-10. As allowed by the phrase, “unless accomplished previously,” if those requirements of AD 2002-10-10 have already been accomplished, this AD does not require that those actions be repeated.
Before the accumulation of 22,000 total flight cycles, or within 3,000 flight cycles after doing the most recent inspection required by paragraph (f) of this AD, whichever occurs later: Do a detailed inspection to find cracking in the areas specified in paragraph (h)(1) or (h)(2), as applicable, in accordance with Figure 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000; or Boeing Service Bulletin 747-53A2349, Revision 2, dated April 3, 2003. After the effective date of this AD, only Boeing Service Bulletin 747-53A2349, Revision 2, may be used. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles. Continue doing the inspection required by this paragraph until the initial inspection required by paragraph (l) of this AD is accomplished. Accomplishment of the inspection in this paragraph terminates the inspections required by paragraph (f) of this AD.
(1) For Groups 1, 2, 4, and 5 airplanes: Do the inspections of Area 1 (sections 41 and 42 upper deck floor beams), including existing repairs and modifications.
(2) For Group 3 airplanes: Do the inspections of Area 1 (sections 41, 42, and 44 upper deck floor beams from body stations 380 through 1100 inclusive), including existing repairs and modifications.
Note 3: For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(i) Before the accumulation of 28,000 total flight cycles, or within 3,000 flight cycles after doing the most recent inspection required by paragraph (f) of this AD, whichever occurs later: Do a high frequency eddy current (HFEC) inspection to find cracking of the open holes in the horizontal flanges of the upper chord of the upper deck floor beams in the areas specified in paragraph (i)(1) or (i)(2) of this AD, as applicable, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000. Do the inspection in accordance with the “Inspection Alternatives” as specified in Sheet 7 of Figure 2 of the Accomplishment Instructions of the service bulletin. Repeat the applicable inspection at the times specified in the “Repeat Inspection Intervals” in Sheet 7 of Figure 2 of the Accomplishment Instructions of the service bulletin. After the effective date of this AD, Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003, must be used to perform the inspections required by this paragraph. Repeat the inspections until the requirements of paragraph (m) of this AD are accomplished.
(1) For Group 1, 2, 4, and 5 airplanes, as defined in Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000: Do the inspections at the applicable locations (BS 380 through BS 780 inclusive for Groups 1, 2, and 4, BS 380 through BS 860 inclusive for Group 5) as specified in Sheet 7 of Figure 2.
(2) For Group 3 airplanes, as defined in Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000: Do the inspections as specified in Sheet 7 of Figure 2, at the upper deck floor beams from BS 380 through BS 1100 inclusive.
Note 4: HFEC inspections of the left and right sides of the upper deck floor beam at body station 380, between buttock lines 40 and 76, done in accordance with AD 2000-04-17 or AD 2005-06-11, are considered acceptable for compliance with the applicable inspections specified in paragraph (i) of this AD.
For the purposes of calculating the compliance threshold and repetitive interval for the actions required by paragraphs (h) and (i) of this AD: The number of flight cycles in which cabin differential pressure is at 2.0 pounds per square inch (psi) or less need not be counted when determining the number of flight cycles that have occurred on the airplane, provided that flight cycles with momentary spikes in cabin differential pressure above 2.0 psi are included as full pressure cycles. For this provision to apply, all cabin pressure records must be maintained for each airplane: No fleet-averaging of cabin pressure is allowed.
Before further flight, repair any cracking found during the inspections done in accordance with paragraphs (h) and (i) of this AD, in accordance with Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000. Where the service bulletin specifies to contact Boeing for repair instructions, repair according to a method approved by the Manager, Seattle ACO; or according to a method approved in accordance with the procedures specified in paragraph (s) of this AD.
Before the accumulation of 22,000 total flight cycles, or within 3,000 flight cycles after the most recent inspection required by paragraph (f) or (h) of this AD, whichever is later: Do a detailed inspection for cracking of the cab floor and of the upper deck floor beams. Do the inspection in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2349, Revision 2, dated April 3, 2003. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles. Doing the initial inspection required by this paragraph terminates the inspections required by paragraphs (f) and (h) of this AD.
Do a HFEC inspection for cracking of the horizontal flanges of the upper chord of the upper deck floor beams, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003, at the applicable time specified in paragraph (m)(1), (m)(2), (m)(3), or (m)(4) of this AD. Areas 1, 2, and 3, as specified in paragraphs (m) and (n) of this AD, are defined in the service bulletin. Accomplishment of this inspection terminates the inspections required by paragraph (i) of this AD.
(1) For airplanes that have not been inspected in accordance with the requirements of paragraph (f), (h), or (i) of this AD:
(i) For Area 1: Before the accumulation of 22,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later.
(ii) For Area 2: Before the accumulation of 28,000 total flight cycles.
(iii) For Area 3: Before the accumulation of 22,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later.
(2) For airplanes that have been inspected in accordance with the requirements of paragraph (f) or (h) of this AD, but not in accordance with the requirements of paragraph (i) of this AD:
(i) For Area 1: Before the accumulation of 22,000 total flight cycles, or within 3,000 flight cycles after the most recent inspection required by paragraph (f) or (h) of this AD, whichever is later.
(ii) For Area 2: Before the accumulation of 28,000 total flight cycles, or within 3,000 flight cycles after the most recent inspection required by paragraph (f) or (h) of this AD, whichever is later.
(iii) For Area 3: Before the accumulation of 22,000 total flight cycles, or within 3,000 flight cycles after the most recent inspection required by paragraph (f) or (h) of this AD, whichever is later.
(3) For airplanes on which a surface HFEC inspection of the horizontal flanges of the upper chord of the upper deck floor beams, as required by paragraph (i) of this AD, was accomplished, and the surface HFEC inspection was accomplished from below the upper deck floor beams as specified by Figure 2, circle note 2c., of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000:
(i) For Area 1: At the later of the times specified in paragraphs (m)(3)(i)(A) and (m)(3)(i)(B) of this AD.
(A) Before the accumulation of 22,000 total flight cycles.
(B) Within 2,000 flight cycles after the most recent inspection required by paragraph (i) of this AD, or 750 flight cycles after the effective date of this AD, whichever is first.
(ii) For Area 2: Before the accumulation of 28,000 total flight cycles, or within 2,000 flight cycles after the most recent inspection required by paragraph (i) of this AD, whichever is later.
(iii) For Area 3: Before the accumulation of 22,000 total flight cycles, or within 3,000 flight cycles after the most recent inspection required by paragraph (f) or (h) of this AD, whichever is later.
(4) For airplanes on which either a surface or open-hole HFEC inspection of the horizontal flanges of the upper chord of the upper deck floor beams, as required by paragraph (i) of this AD has been accomplished, and the surface HFEC inspection was accomplished from above and below the upper deck floor beams, as specified by Figure 2, circle note 2b., of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000:
(i) For Area 1: At the later of the times specified in paragraphs (m)(4)(i)(A) and (m)(4)(ii)(B) of this AD.
(A) Before the accumulation of 22,000 total flight cycles.
(B) Within 6,000 flight cycles after the most recent inspection required by paragraph (i) of this AD, or within 3,000 flight cycles after the effective date of this AD whichever is first.
(ii) For Area 2: Before the accumulation of 28,000 total flight cycles, or within 6,000 flight cycles after the most recent inspection required by paragraph (i) of this AD, whichever is later.
(iii) For Area 3: Before the accumulation of 22,000 total flight cycles, or within 3,000 flight cycles after the most recent inspection required by paragraph (f) or (h) of this AD, whichever is latest.
Except as required by paragraphs (o), (p), and (q) of this AD, repeat the inspections required by paragraph (m) of this AD at intervals not to exceed those specified in paragraphs (n)(1), (n)(2), and (n)(3) of this AD:
(1) For Area 1: 3,000 flight cycles if an open-hole HFEC inspection was accomplished, or 750 flight cycles if a surface HFEC inspection was accomplished.
(2) For Area 2: 6,000 flight cycles if an open-hole HFEC inspection was accomplished, or 2,000 flight cycles if a surface HFEC inspection was accomplished.
(3) For Area 3: 3,000 flight cycles.
Before further flight, repair any cracking found during any inspection required by paragraph (l), (m), or (n) of this AD in accordance with Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003. Repairs done in accordance with this service bulletin terminates the requirements of paragraphs (l), (m), and (n) of this AD for the repaired area only. Where the service bulletin specifies to contact Boeing for repair instructions, repair according to a method approved by the Manager, Seattle ACO; or according to a method approved in accordance with the procedures specified in paragraph (s) of this AD.
At the applicable new inspection thresholds specified in Figure 1 of Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003, perform the after-repair inspections for cracking in Areas 1 and 2, as specified in the service bulletin. Where the service bulletin specifies a threshold after the date of the service bulletin, use that same threshold after the effective date of this AD. Perform the after-repair inspections by accomplishing all of the applicable actions specified in the alert service bulletin. Repair any cracking found during any inspection required by this paragraph, according to a method approved by the Manager, Seattle ACO; or according to a method approved in accordance with the procedures specified in paragraph (s) of this AD. Any cracking found during any inspection must be repaired before further flight. Repeat the inspections of Areas 1 and 2 thereafter at intervals not to exceed 3,000 flight cycles.
If no cracking was found during the open-hole HFEC inspections required by paragraph (m) or (n) of this AD, repairing or modifying Areas 1 and 2, as defined in Figure 1 of Boeing Alert Service Bulletin 747-53A2452, dated April 3, 2003, in accordance with the service bulletin, defers the repetitive inspections required by paragraph (n) of this AD, and establishes new inspection methods, thresholds, and repetitive inspection intervals for the repaired or modified area. The new inspection thresholds and intervals are specified in Figure 1 of the service bulletin. Where the service bulletin specifies a threshold after the date of the service bulletin, use that same threshold after the effective date of this AD.
Doing the inspections required by paragraphs (m) and (n) of this AD before the effective date of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000, is acceptable for compliance with the corresponding actions required by this AD.
