Airworthiness Directive · Amendment 39-14020 · 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 Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR series airplanes; line numbers 1 through 810 inclusive; certificated in any category; and not equipped with a nose cargo door.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR series airplanes. That AD currently requires one-time inspections for cracking in certain upper deck floor beams and follow-on actions. This new AD expands the existing inspection area and requires inspecting fastener holes in certain areas of airplanes modified previously, and taking corrective actions if necessary. This action also defines new sources for instructions for repairs and post-modification/repair inspections. This AD is prompted by reports of fatigue cracking of the upper chord of certain upper deck floor beams. We are issuing this AD to find and fix cracking in certain upper deck floor beams, which could extend and sever floor beams adjacent to the body frame and result in rapid depressurization 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.
At the compliance time specified in paragraph (f)(1) or (f)(2) of this AD, as applicable, perform one-time detailed and open-hole high-frequency eddy current (HFEC) inspections for cracking in the upper deck floor beams at station (STA) 340 and STA 360, in accordance with Boeing Alert Service Bulletin 747-53A2459, dated January 11, 2001; or Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004. As of the effective date of this AD, only Revision 1 may be used. For the purposes of this AD, flight cycles with a cabin differential pressure of 2.0 psi or less are not calculated into the compliance thresholds specified in this AD. However, all cabin pressure records must be maintained for each airplane, and no fleet averaging of cabin pressure is allowed.
Note 1: For the purposes of this AD, a detailed inspection is: “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.”
(1) For airplanes with 22,000 or fewer total flight cycles as of October 16, 2002 (the effective date of AD 2002-18-04): Do the inspections prior to the accumulation of 16,000 total flight cycles, or within 1,500 flight cycles after October 16, 2002, whichever is later.
(2) For airplanes with more than 22,000 total flight cycles as of the effective date of this AD: Do the inspections within 500 flight cycles after October 16, 2002.
If no crack is found during the inspections in accordance with paragraph (f) of this AD: Within 5,000 flight cycles after the initial inspections, modify the upper deck floor beams at STA 340 and STA 360, in accordance with Boeing Alert Service Bulletin 747-53A2459, dated January 11, 2001; or Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004. As of the effective date of this AD, only Revision 1 may be used. If this modification is not done before further flight after the inspections required by paragraph (f) of this AD, those inspections must be repeated one time, immediately before accomplishing the modification in this paragraph. If any crack is found during these repeat inspections, before further flight, accomplish paragraph (h)(2) of this AD.
If any crack is found during the inspections in accordance with paragraph (f) of this AD: Before further flight, repair in accordance with either paragraph (h)(1) or (h)(2) of this AD.
(1) Accomplish repairs in accordance with paragraphs (h)(1)(i) and (h)(1)(ii) of this AD.
(i) Accomplish a time-limited repair (including removing certain fasteners and the existing strap, performing open-hole HFEC inspections of the chord and web, stop-drilling web cracks, replacing the outboard section of the web, if applicable, and installing new straps) in accordance with Boeing Alert Service Bulletin 747-53A2459, dated January 11, 2001; or Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004; except where the service bulletin specifies to contact Boeing for appropriate action, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative (DER), or an Authorized Representative (AR) for the Boeing Delegation Option Authorization (DOA) Organization, who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved as required by this paragraph, the approval must specifically reference this AD. As of the effective date of this AD, only Revision 1 of the service bulletin may be used.
(ii) Within 18 months or 1,500 flight cycles after installation of the time-limited repair in accordance with paragraph (h)(1)(i) of this AD, whichever is first, do paragraph (h)(2) of this AD.
(2) Accomplish a permanent repair in accordance with Boeing Alert Service Bulletin 747-53A2459, dated January 11, 2001; or Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004; except where the service bulletin specifies to contact Boeing for appropriate action, repair in accordance with a method approved by the Manager, Seattle ACO; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company DER, or an AR for the Boeing DOA Organization, who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved as required by this paragraph, the approval must specifically reference this AD. As of the effective date of this AD, only Revision 1 of the service bulletin may be used.
(i) Within 15,000 flight cycles after modification of the upper deck floor beams in accordance with paragraph (g) of this AD, or after permanent repair of the upper deck floor beams in accordance with paragraph (h) of this AD, as applicable: Perform either open-hole HFEC inspections for cracking of fastener holes common to the upper chord, reinforcement straps, and the body frame; or surface HFEC inspections for cracking along the lower edge of the upper chord of the floor beam at the intersection with the body frame; and repeat these inspections at the interval specified in paragraph (i)(1) or (i)(2) of this AD, as applicable, until the initial inspection required by paragraph (l) of this AD is complete. Perform these inspections and repair any cracking found during these inspections in accordance with a method approved by the Manager, Seattle ACO, or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company DER, or an AR for the Boeing DOA Organization, who has been authorized by the Manager, Seattle ACO, to make such findings. For an inspection or repair method to be approved as required by this paragraph, the approval must specifically reference this AD.
(1) If the most recent inspection used the surface HFEC method: Repeat the inspection within 1,000 flight cycles.
(2) If the most recent inspection used the open-hole HFEC method: Repeat the inspection every 3,000 flight cycles.
Note 2: Instructions for post-modification/repair inspections are not provided in the original issue of Boeing Alert Service Bulletin 747-53A2459, dated January 11, 2001.
For airplanes on which the inspection in paragraph (f) of this AD has been done prior to the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-53A2459, dated January 11, 2001, but the modification specified in paragraph (g) or the permanent repair specified in paragraph (h) of this AD has not been done: At the applicable time specified in Table 1 of this AD, do a one-time open-hole HFEC inspection for cracking of the fastener holes inboard of the body frame that were not previously inspected on the STA 340 and STA 360 upper deck floor beams. Do this inspection in accordance with Part 1 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004.
| Total number of accumulated flight cycles as of the effective date of this AD | Compliance time |
|---|---|
| 22,000 or fewer | Within 5,000 flight cycles after the initial open-hole HFEC inspection for cracking in accordance with paragraph (f) of this AD, or within 1,000 flight cycles after the effective date of this AD, whichever is later. |
| 22,001 or more | Prior to the accumulation of 25,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later. |
For airplanes on which the modification specified in paragraph (g) or the permanent repair specified in paragraph (h) of this AD has been done prior to the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-53A2459, dated January 11, 2001: At the applicable time specified in Table 2 of this AD, do a one-time open-hole HFEC inspection for cracking of fastener holes common to the modification straps, in accordance with Part 6 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004.
| Total number of accumulated flight cycles when the modification or permanent repair was done | Compliance time |
|---|---|
| 22,000 or fewer | Within 3,000 flight cycles after doing the modification or permanent repair, or 1,000 flight cycles after the effective date of this AD, whichever is later. |
| 22,001 or more | Within 1,500 flight cycles after doing the modification or permanent repair, or 1,000 flight cycles after the effective date of this AD, whichever is later. |
Do open-hole HFEC inspections for cracking of the STA 340 and STA 360 upper deck floor beams at fastener holes common to the upper chord, reinforcement straps, and body frame; or do surface HFEC inspections for cracking along the lower edge of the upper chord and reinforcement straps of the floor beams. Do the applicable inspection in accordance with Part 5 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004. Do the initial inspections at the applicable times specified in Table 3 of this AD, and repeat the inspection at the applicable interval specified in Figure 9 of the service bulletin. Completing the initial inspection required by this paragraph terminates the repetitive inspections required by paragraph (i) of this AD. For airplanes on which paragraph (i) of this AD has not been done, doing the initial inspection required by this paragraph at the specified compliance time eliminates the need to comply with paragraph (i) of this AD. For the purposes of this paragraph and Table 3 of this AD, an inspection in accordance with Part 6, Figure 14, of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2459, Revision 1, is equivalent to an inspection in accordance with Part 5, Figure 12, of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2459, Revision 1.
| For the inspections identified in the following figures referenced in Figure 9 of the service bulletin— | For these airplanes— | Do the inspection— |
|---|---|---|
| Figure 10 or 11 | Airplanes not inspected previously in accordance with paragraph (i) of this AD | Within 15,000 flight cycles after doing the modification or permanent repair. |
| Figure 10 or 11 | Airplanes inspected previously in accordance with paragraph (i) of this AD using the surface HFEC method for the most recent inspection | Within 1,000 flight cycles after the most recent inspection. |
| Figure 10 or 11 | Airplanes inspected previously in accordance with paragraph (i) of this AD using the open-hole HFEC method for the most recent inspection | Within 3,000 flight cycles after the most recent inspection. |
| Figure 12 or 13 | All airplanes | Within 6,000 flight cycles after doing the modification or permanent repair, or within 1,000 flight cycles after the effective date of this AD, whichever is later. |
If any crack is found during any inspection required by paragraph (j), (k), or (l) of this AD: Before further flight, repair in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004; except where the service bulletin specifies to contact Boeing for appropriate action, repair in accordance with a method approved by the Manager, Seattle ACO; or in accordance with data meeting the type certification basis of the airplane approved by an AR for the Boeing DOA Organization who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD.
Although Boeing Service Bulletin 747-53A2459, Revision 1, dated March 11, 2004, specifies to report certain body frame cracks on certain airplanes, this AD does not include that requirement.
