AD 2008-17-17

We are adopting a new airworthiness directive (AD) for all Boeing Model 747 airplanes. This AD requires a one-time inspection of certain fuselage skins at section 41 to find any external doublers that cover the inspection areas and to identify the external doublers that end on a stringer and those that do not, and related investigative and corrective actions if necessary. This AD results from reports of cracks found at fastener locations in the fuselage skins at section 41. We are issuing this AD to detect and correct fuselage skin cracks at fastener locations along the skin-to-stringer attachments, which could join together and become large and consequently result in rapid decompression of the cabin.

Final rule.

2008-17-17 Boeing: Amendment 39-15655. Docket No. FAA-2008-0148; Directorate Identifier 2007-NM-299-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective October 2, 2008. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to all 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. \n\nUnsafe Condition \n\n\t(d) This AD results from reports of cracks found at fastener locations in the fuselage skins at section 41. We are issuing this AD to detect and correct fuselage skin cracks at fastener locations along the skin-to-stringer attachments, which could join together and become large and consequently result in rapid decompression of the cabin. \n\nCompliance \n\n\t(e) Comply with this AD within the compliance times specified, unless already done. \n\nRepetitive Inspections and Related Investigative/Corrective Actions \n\n\t(f) At the applicable compliance times specified in Tables 1 and 2 of paragraph 1.E. of Boeing Alert Service Bulletin 747-53A2704, dated October 4, 2007: Do a general visual inspection of the fuselage skins at section 41 to find any external doublers that cover the inspection area and to identify the external doublers that end on a stringer in the inspection area and those that do not, and do all the related investigative and corrective actions as applicable, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of the service bulletin, except as provided by paragraph (g) of this AD. Repeat the related investigative actions thereafter at the interval specified in Tables 1 and 2 of the service bulletin, as applicable. \n\nExceptions to the Service Bulletin \n\n\t(g) Where Tables 1 and 2 of paragraph 1.E. of Boeing Alert Service Bulletin 747-53A2704, dated October 4, 2007, specify counting the compliance time from " * * * after the date on thisservice bulletin,'' this AD requires counting the compliance time from the effective date of this AD. Where Figure 19 of the service bulletin specifies doing a "detailed visual inspection'' for any crack at fastener holes common to the stringer, this AD requires doing a detailed inspection. In Figure 3 of the service bulletin, also inspect the areas at stringer 5 (S-5) and S-5A between station (STA) 340 and STA 360 (similar to Figure 8 for the right side). In Figure 15 of the service bulletin, also inspect the area at S-14A between STA 200 and STA 220 (similar to Figure 17 for the right side). \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6437; fax (425) 917-6590; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. \n\t(2) Torequest a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. \n\t(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. \n\nMaterial Incorporated by Reference \n\n\t(i) You must use Boeing Alert Service Bulletin 747-53A2704, dated October 4, 2007, to do the actions required by this AD, unless the AD specifies otherwise.(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. \n\t(2) For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. \n\t(3) You may review copies of the service information incorporated by reference at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_ regulations/ibr_locations.html.

Discussion \n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to all Boeing Model 747 airplanes. That NPRM was published in the Federal Register on February 8, 2008 (73 FR 7486). That NPRM proposed to require a one-time inspection of certain fuselage skins at section 41 to find any external doublers that cover the inspection areas and to identify the external doublers that end on a stringer and those that do not, and related investigative and corrective actions if necessary. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We considered the comments received from the two commenters. \n\nSupport for the NPRM \n\n\tBoeing concurs with the contents of the NPRM. \n\nRequest to Either Delay Issuance of the AD or Extend the Compliance Time \n\n\tJapan Airlines (JAL) requests that we delay issuance of the AD until Boeing has published arevision to Boeing Alert Service Bulletin 747-53A2704, dated October 4, 2007, to extend the compliance time from 16,000 total flight cycles to 25,000 total flight cycles for accomplishing the general visual inspection for external doublers in Areas 2 and 3. If we cannot delay issuance of the AD, then JAL requests that we revise the compliance time accordingly in this AD. JAL states that Boeing has advised that only the inspection of Area 1 must be done before 16,000 total flight cycles, and that Areas 2 and 3 should be inspected together with the high frequency eddy current inspection of the skin-to-stringer attachments before 25,000 total flight cycles. JAL asserts that Boeing will revise the compliance time in the next revision to the service bulletin. \n\tWe do not agree to delay issuance of this AD, or to revise the compliance time for inspecting for external doublers in Areas 2 and 3. We have coordinated with Boeing, and Boeing has no plans, at this time, to revise the service bulletin. Boeing also has confirmed that the inspection of Areas 1, 2, and 3 was left at 16,000 total flight cycles for simplicity of the compliance table in the service bulletin. Therefore, we agree that, for Groups 1 through 5 airplanes, \nthe general visual inspection for external doublers in Areas 2 and 3 may be done before 25,000 total flight cycles, or within 2,000 flight cycles after the effective date of this AD, whichever occurs later. However, due to the unique nature of JAL's request, it would be best to address it using the alternative methods of compliance (AMOC) process, rather than revising this AD. We will consider requests for adjustments to the compliance time, under the provisions of paragraph (h) of this AD, if data are submitted to substantiate that such an adjustment would provide an acceptable level of safety. We have not changed the AD in this regard. \n\nConclusion \n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safetyand the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tWe estimate that this AD affects 165 airplanes of U.S. registry. We also estimate that it takes up to 64 work-hours per product to comply with this AD. The average labor rate is $80 per work-hour. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $844,800 or $5,120 per product. \n\nAuthority for This Rulemaking \n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. "Subtitle VII: Aviation Programs,'' describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in "Subtitle VII, Part A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\tThis AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a "significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and \n\t(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of theRegulatory Flexibility Act. \n\tYou can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The FAA amends Sec. 39.13 by adding the following new AD: