AD 2009-16-14

The FAA is superseding an existing airworthiness directive (AD) that applies to certain Boeing Model 737-100, -200, -200C, -300, - 400, and -500 series airplanes. That AD currently requires repetitive inspections of the intercostal webs, attachment clips, and stringer splice channels for cracks; and corrective action if necessary. This new AD reduces the repetitive inspection intervals from 25,000 flight cycles to 6,000 flight cycles, and expands the inspection area for Model 737-200C series airplanes to include the area aft of the forward entry door. This AD results from additional reports of fatigue cracks. We are issuing this AD to detect and correct fatigue cracking of the intercostals on the forward and aft sides of the forward entry door, which could result in loss of the forward entry door and rapid decompression of the airplane.

Final rule.

2009-16-14 Boeing: Amendment 39-15987. Docket No. FAA-2008-1213; Directorate Identifier 2007-NM-092-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective September 9, 2009. \n\nAffected ADs \n\n\t(b) This AD supersedes AD 2005-20-03. \n\nApplicability \n\n\t(c) This AD applies to Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007. \n\nUnsafe Condition \n\n\t(d) This AD results from reports of fatigue cracks. We are issuing this AD to detect and correct fatigue cracking of the intercostals on the forward and aft sides of the forward entry door, which could result in loss of the forward entry door and 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\nInitial Compliance Time \n\n\t(f) For all Model 737-100, -200, -200C, -300, -400, and -500 series airplanes: Before the accumulation of 15,000 total flight cycles, or within 4,500 flight cycles after November 1, 2005 (the effective date of AD 2005-20-03), whichever occurs later: Do the inspections required by paragraphs (h) and (i) of this AD. \n\t(g) For all Model 737-200C series airplanes: Before the accumulation of 15,000 total flight cycles, or within 4,500 flight cycles after the effective date of this AD, whichever occurs later: Do the inspection required by paragraph (j) of this AD. \n\nInitial Inspection for Passenger Configuration Airplanes \n\n\t(h) For Group 1 passenger airplanes identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: Perform a detailed inspection for cracking of the intercostal web, attachment clips, and stringer splice channels; and a high frequency eddy current inspection for cracking of the stringer splice channels located forward and aft of the forwardentry door; and do all applicable corrective actions before further flight; in accordance with Parts 1 and 2 of the Work Instructions of Boeing Special Attention Service Bulletin 737-53- 1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737- 53A1204, Revision 1, dated March 26, 2007. After the effective date of this AD, only Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007, may be used. \n\nInitial Inspection for Cargo Configuration Airplanes (Forward of the Forward Entry Door) \n\n\t(i) For Group 2 cargo airplanes identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: Perform a detailed inspection for cracking of the intercostal webs and attachment clips located forward of the forward entry door, and do all applicable corrective actions before further flight, in accordance with Part 3 of the Work Instructions of Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007. After the effective date of this AD, only Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007, may be used. \n\nInitial Inspection for Cargo Configuration Airplanes (Aft of the Forward Entry Door) \n\n\t(j) For Group 2 cargo airplanes identified in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: Perform a detailed inspection for cracking of the intercostal webs and attachment clips located aft of the forward entry door, and do all applicable corrective actions before further flight, in accordance with Part 4 of the Work Instructions of Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007. \n\nRepeat Inspections \n\n\t(k) Repeat the inspections required by paragraphs (h), (i), and (j) of this AD thereafter at intervals not to exceed 6,000 flight cycles after the previous inspection, or within 3,000 flight cycles after the effective date of this AD, whichever occurs later. \n\nExceptions \n\n\t(l) Do the actions required by this AD by accomplishing all the applicable actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; except as provided by paragraphs (l)(1) and (l)(2) of this AD. After the effective date of this AD, only Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007, may be used. \n\t(1) Where Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (m) of this AD. \n\t(2) Where Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; specifies a compliance time relative to the date of a service bulletin, this AD requires compliance relative to the effective date of this AD. Where Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; specifies a compliance time relative to the date of the initial release of the service bulletin, this AD requires compliance relative to the effective date of AD 2005-20-03 (November 1, 2005). \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(m)(1) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Alan Pohl, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6450; fax (425) 917-6590. \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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD. \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\t(4) AMOCs approved previously in accordance with AD 2005-20-03 are approved as AMOCs for the corresponding provisions of thisAD, provided the repetitive inspection intervals (if any) do not exceed 6,000 flight cycles. \n\t(5) AMOCs approved previously in accordance with AD 2005-20-03 are not approved as AMOCs for the provisions of paragraph (j) or (k) of this AD. \n\nMaterial Incorporated by Reference \n\n\t(n) You must use Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; as applicable; to do the actions required by this AD, unless the AD specifies otherwise. \n\t(1) The Director of the Federal Register approved the incorporation by reference of Boeing Alert Service Bulletin 737- 53A1204, Revision 1, dated March 26, 2007, 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, Attention: Data & Services Management, P. O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. \n\t(3) You mayreview copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221 or 425-227-1152. \n\t(4) You may also review copies of the service information that is incorporated by reference 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\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that supersedes AD 2005-20-03, amendment 39-14296 (70 FR 56361, September 27, 2005). The existing AD applies to certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. That NPRM was published in the Federal Register on November 17, 2008 (73 FR 67815). That NPRM proposed to continue to require repetitive inspections of the intercostal webs, attachment clips, and stringer splice channels for cracks, at repetitive inspection intervals reduced from 25,000 flight cycles to 6,000 flight cycles; and corrective action if necessary. That NPRM also proposed to expand the inspection area for Model 737-200C series airplanes to include the area aft of the forward entry door. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been received onthe NPRM. \n\nRequest to Increase Grace Period \n\n\tUS Airways requests that we increase the threshold grace period from 3,000 flight cycles after the effective date of this AD to 4,500 flight cycles. US Airways states that the new grace period it requests would allow operators to schedule more airplanes into appropriate maintenance tasks. US Airways explains that the inspection would affect its operation by requiring additional maintenance that is not presently scheduled. \n\tWe do not agree with the commenter's request. In developing an appropriate compliance time for this AD, we considered not only the safety implications, but the manufacturer's recommendations, and the practical aspect of accomplishing the modification within an interval of time that corresponds to typical scheduled maintenance for affected operators. However, under the provisions of paragraph (m) of this AD, we may consider requests for adjustments to the compliance time if data are submitted to substantiate thatsuch an adjustment would provide an acceptable level of safety. We have not changed this AD in this regard. \n\nExplanation of Additional Changes to the AD \n\n\tWe have clarified paragraphs (h), (i), and (l) of this AD to include the full citation for the service information referenced in those paragraphs. We made this change to ensure that it is clear which service information operators must use for a specific action. \n\tWe have changed paragraph (j) of this AD to remove the reference to "Part 4 of the Work Instructions of Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003,'' because that service bulletin does not contain a Part 4. Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007, does include Part 4 to provide procedures related to inspections and corrective actions for the intercostal webs and attachment clips located aft of the forward entry door. Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003, does notinclude any actions for this area of the airplane. \n\nConclusion \n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD. \n\nCosts of Compliance \n\n\tThere are about 3,132 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tEstimated Costs\n\n\nAction\nWork hours\nAverage labor rate per hour\nCost per airplane\nNumber of U.S.-registered airplanes\nFleet cost\nInspection of areas forward of the aft entry door (required by AD 2005-20-03)\n2\n$80\n$160 per inspection cycle\n876\n$140,160 per inspection cycle\nInspection of areas aft of the forward entry door for Model 737-200C series airplanes (new action)\n1\n$80\n$80 per inspection cycle\n19\n$1,520 per inspection cycle\n \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\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\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 the Regulatory Flexibility Act. \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 removing amendment 39-14296 (70 FR 56361, September 27, 2005) and by adding the following new airworthiness directive (AD):