AD 2007-25-17

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747- 200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. This AD requires repetitive inspections for cracking of the station (STA) 1241 bulkhead fittings just above the canted pressure deck; a one-time determination of the edge margin at seven fastener positions on each side of the airplane; and related investigative/corrective actions if necessary. This AD results from a report that an operator found a 1.65- inch crack on the STA 1241 bulkhead fitting on the left side of a Boeing Model 747-200F series airplane that had accumulated 17,332 total flight cycles. We are issuing this AD to detect and correct cracking in the STA 1241 bulkhead fittings, which could result in reduced structural integrity of the airplane.

Final rule.

2007-25-17 Boeing: Amendment 39-15299. Docket No. FAA-2007-28620; Directorate Identifier 2007-NM-090-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective January 14, 2008. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2658, dated February 22, 2007. \n\nUnsafe Condition \n\n\t(d) This AD results from a report that an operator found a 1.65- inch crack on the station (STA) 1241 bulkhead fitting on the left side of a Boeing Model 747-200F series airplane that had accumulated 17,332 total flight cycles. We are issuing this AD to detect and correct cracking in the STA 1241 bulkhead fittings, which could result in reduced structural integrity of the airplane. \n\nCompliance \n\n\t(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. \n\nInspections and Corrective Action \n\n\t(f) At the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 747-53A2658, dated February 22, 2007: Do internal surface high-frequency eddy current and external ultrasonic inspections for cracking of the STA 1241 bulkhead fittings just above the canted pressure deck; determine the edge margin at seven fastener positions on each side of the airplane; and do all applicable related investigative/corrective actions; by doing all of the actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2658, dated February 22, 2007, except as provided by paragraphs (f)(1) and (f)(2) of this AD. Do all applicable related investigative/ corrective actions before further flight. Repeat the inspections thereafter at the applicable interval specified in paragraph 1.E., ''Compliance'' of the service bulletin. \n\n\t(1) Where the service bulletin specifies to contact Boeing for appropriate action, before further flight, do the action using a method approved in accordance with the procedures specified in paragraph (g) of this AD. \n\n\t(2) Where the service bulletin specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(g)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. \n\n\t(2) To request 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\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(h) You must use Boeing Alert Service Bulletin 747-53A2658, dated February 22, 2007, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at theFAA, 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/cfr/ibr-locations.html.

Discussion \n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. That NPRM was published in the Federal Register on July 9, 2007 (72 FR 37130). That NPRM proposed to require repetitive inspections for cracking of the station (STA) 1241 bulkhead fittings just above the canted pressure deck; a one-time determination of the edge margin at seven fastener positions on each side of the airplane; and related investigative/corrective actions if necessary. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comments received. Request to Revise ''Relevant Service Information'' Section \n\n\tBoeing asks that we revise the first sentence in the fourth paragraph of the ''Relevant Service Information'' section of the NPRM. That sentence now reads: ''For airplanes modified in accordance with Boeing Service Bulletin 747-53-2283 (AD 90-06-06). * * *'' Because Boeing Service Bulletin 747-53-2283 describes four different procedures and the modification referred to in the NPRM is a splice strap replacement, Boeing requests that the sentence read: ''For airplanes modified by replacing the splice strap in accordance with Boeing Service Bulletin 747-53-2283, Part III, Splice Strap Replacement and Boeing drawing 624U0006 * * *'' \n\n\tWe agree that the requested change clarifies the explanation in the ''Relevant Service Information'' section in the preamble of the NPRM. However, since that section of the preamble does not reappear in the final rule, no change to the final rule is necessary. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tThere are about 455 airplanes of the affected design in the worldwide fleet. This AD affects about 133 airplanes of U.S. registry. The actions take about 14 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the AD for U.S. operators is $148,960, or $1,120 per airplane, per inspection cycle. \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\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\tWe have determined that this 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\n\tFor the reasons discussed above, I certify that this AD: \n\n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866; \n\n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\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\n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation. \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 Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):