AD 2007-25-03

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. This AD requires repetitive inspections of either the aft side or forward side of the aft pressure bulkhead for oil can conditions or bulges, a one-time inspection of the aft pressure bulkhead to identify any previously installed web repair, and corrective actions if necessary. This AD results from web oil can conditions found on the aft pressure bulkhead of several airplanes. We are issuing this AD to detect and correct oil can conditions, bulges, or previous repairs in the aft pressure bulkhead, which could lead to web cracks and consequently result in rapid decompression of the airplane.

Final rule.

2007-25-03 Boeing: Amendment 39-15284. Docket No. FAA-2007-29031; Directorate Identifier 2007-NM-130-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 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-53A1253, dated May 18, 2007. \n\nUnsafe Condition \n\n\t(d) This AD results from web oil can conditions found on the aft pressure bulkhead of several airplanes. We are issuing this AD to detect and correct oil can conditions, bulges, or previous repairs in the aft pressure bulkhead, which could lead to web cracks and consequently result in rapid decompression 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\nRepetitive Inspections \n\n\t(f) Atthe applicable times specified in paragraph 1.E. of Boeing Alert Service Bulletin 737-53A1253, dated May 18, 2007, except as provided by paragraph (g) of this AD: Do repetitive general visual inspections of either the aft side or forward side of the aft pressure bulkhead for oil can conditions or bulges and a one-time general visual inspection of the aft pressure bulkhead to identify any previously installed web repair, and do all applicable corrective actions, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1253, dated May 18, 2007, except as provided by paragraphs (h) and (i) of this AD. \n\nExceptions to Compliance Times \n\n\t(g) Where Tables 1 and 2 of paragraph 1.E. of Boeing Alert Service Bulletin 737-53A1253, dated May 18, 2007, specify a compliance time of "at or before 15,000 total flight cycles or within 1,200 flight cycles'' for the general visual inspections, this AD requires accomplishing the applicable inspection at the later of those compliance times. Where Tables 1 and 2 of paragraph 1.E. of the service bulletin specify counting the compliance time from the "release date of this service bulletin'' or "after the date on this service bulletin,'' this AD requires starting the compliance time from the effective date of this AD. Where Table 2 of paragraph 1.E. of the service bulletin specifies to determine the FAA-approved, follow-on inspection procedures, thresholds, and repeat intervals and to incorporate them into the airplane maintenance program within 12 months after accomplishing the inspection given in Section 53-80-08-2R of the Boeing 737-600/700/ 700C/800/900 Structural Repair Manuals (SRMs), this AD requires that those corrective actions, if applicable, be done within 12 months after accomplishing the one-time general visual inspection of the aft pressure bulkhead for any previously installed web repair as required by paragraph (f) of this AD. \n\nExceptions to Corrective Actions \n\n\t(h) If any crack or bulge is found during any inspection required by paragraph (f) of this AD and Boeing Alert Service Bulletin 737-53A1253, dated May 18, 2007, specifies to contact Boeing for repair instructions, before further flight, repair 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 by an Authorized Representative for the Boeing 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. If a previously installed aft pressure bulkhead web repair is found during any inspection required by paragraph (f) of this AD, and the FAA-approved supplemental inspection program cannot be determined from either the Boeing 737- 600/700/700C/800/900 SRMs or the service bulletin, and the service bulletin specifies to contact Boeing for further instructions, within 12 months after accomplishing the inspection contact the Manager, SACO, or an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization to develop a supplemental inspection program. \n\nNo Reporting Requirement \n\n\t(i) Although Boeing Alert Service Bulletin 737-53A1253, dated May 18, 2007, specifies to submit certain information to the manufacturer, this AD does not require that action. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(j)(1) The Manager, Seattle ACO, 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 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD. \n\nMaterial Incorporated by Reference \n\n\t(k) You must use Boeing Alert Service Bulletin 737-53A1253, dated May 18, 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 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/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 737-600, -700, -700C, -800, and -900 series airplanes. That NPRM was published in the Federal Register on August 24, 2007 (72 FR 48594). That NPRM proposed to require repetitive inspections of either the aft side or forward side of the aft pressure bulkhead for oil can conditions or bulges, a one-time inspection of the aft pressure bulkhead to identify any previously installed web repair, and 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 two comments received. Boeing and Continental Airlines support the NPRM. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comments 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 1,755 airplanes of the affected design in the worldwide fleet. This AD affects about 600 airplanes of U.S. registry. The required inspection takes about 6 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 $288,000, or $480 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 the Regulatory 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):