AD 2010-22-04

We are superseding an existing airworthiness directive (AD) for the products listed above. That AD currently requires a detailed inspection for certain defects of the upper fasteners of the aft mount support fittings of the left and right engines, and corrective actions if necessary. This new AD requires repetitive replacement of the upper row of fasteners of the support fittings of the engine aft mount with new fasteners; and repetitive general visual inspections for defects of the lower row fasteners (Row B) of the support fittings of the left and right engine aft mounts, and replacement of all clearance fit fasteners in the lower row if necessary. This AD was prompted by reports of loose, cracked, or missing fasteners in the aft mount support fitting of the left and right engines. We are issuing this AD to prevent loose, cracked, or missing fasteners in the engine aft mount support fittings, which could lead to separation of the support fittings from the pylon, and could result in separation of the engine from the airplane.

Final rule.

2010-22-04 McDonnell Douglas Corporation: Amendment 39-16483; Docket No. FAA-2010-0645; Directorate Identifier 2009-NM-200-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective December 3, 2010. \n\nAffected ADs \n\n\t(b) This AD supersedes AD 2008-18-10, Amendment 39-15667. \n\nApplicability \n\n\t(c) This AD applies to McDonnell Douglas Corporation Model MD- 90-30 airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. \n\nSubject \n\n\t(d) Air Transport Association (ATA) of America Code 54: Nacelles/Pylons. \n\nUnsafe Condition \n\n\t(e) This AD results from reports of loose, cracked, or missing fasteners in the aft mount support fitting of the left and right engines. The Federal Aviation Administration is issuing this AD to prevent loose, cracked, or missing fasteners in the engine aft support mount fittings, which could lead to separation of the support fittings from the pylon, and could result in separation of the engine from the airplane. \n\nCompliance \n\n\t(f) 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\nReplacement and Inspection \n\n\t(g) Except as required by paragraph (i) of this AD, at the applicable time specified in paragraph 1.E., "Compliance,'' of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010: Replace the upper row of fasteners (Row A) of the support fittings of the left and right engine aft mounts with new fasteners, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. Repeat the replacement thereafter at intervals not to exceed 10,000 flight cycles. \n\n\t(h) Concurrently with any replacement required by paragraph (g) of this AD: Perform a general visual inspection for defects of the lower row fasteners (Row B) of the support fittings of the left and right engine aft mounts, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. Defects include missing, loose, and damaged fasteners. \n\n\t(1) If no defect is found during any general visual inspection required by paragraph (h) of this AD, before further flight, insert a 0.0015-inch feeler gauge between the washer and the structure, or between the fastener head and structure, as applicable, to detect a gap condition, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. A gap condition is a defect identified in any location where the feeler gauge can slip completely between a washer or a fastener head and the structure. \n\n\t(i) If no defect is found during any gap check required by paragraph (h)(1) of this AD, before further flight, apply torque to the fasteners of the lower row (Row B) to determineif there is a defect, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. A defect is any fastener that turns with the application of the specified torque. If any defect is found, before further flight, replace all clearance fit fasteners in the lower row (Row B), in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. \n\n\t(ii) If any defect is found during any gap check required by paragraph (h)(1) of this AD, before further flight, replace all clearance fit fasteners in the lower row (Row B), in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. \n\n\t(2) If any defect is found during any general visual inspection required by paragraph (h) of this AD, before further flight, replace all clearance fit fasteners in the lower row (Row B), in accordancewith the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010. \n\nException to Service Bulletin Compliance Times \n\n\t(i) Where Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010, specifies a compliance time after the original issue date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD. \n\nCredit for Actions Accomplished in Accordance With Previous Service Information \n\n\t(j) Replacements and inspections accomplished before the effective date of this AD in accordance with Boeing Alert Service Bulletin MD90-54A003, Revision 1, dated November 17, 2009, are considered acceptable for compliance with the corresponding actions required by this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(k)(1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD. \n\n\t(2) Before using any approved AMOC, notify your Principal Maintenance Inspector or Principal Avionics Inspector, as appropriate, or lacking a principal inspector, your local Flight Standards District Office. \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 the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Los Angeles 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\nRelated Information \n\n\t(l) For more information about this AD, contact Roger Durbin, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5233; fax (562) 627-5210; e-mail: Roger.Durbin@faa.gov. \n\nMaterial Incorporated by Reference \n\n\t(m) You must use Boeing Alert Service Bulletin MD90-54A003, Revision 2, dated February 12, 2010, to do the actions required by this AD, unless the AD specifies otherwise. \n\n\t(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\n\t(2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, 3855 Lakewood Boulevard, MC D800 0019, Long Beach, California 90846- 0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail dse.boecom@boeing.com; Internet https://www.myboeingfleet.com. \n\n\t(3) You may review copies of the service information at the FAA, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221. \n\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 an NARA facility, 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 supersede airworthiness directive (AD) 2008-18-10, amendment 39-15667 (73 FR 52203, September 9, 2008). That AD applies to the specified products. The NPRM was published in the Federal Register on July 1, 2010 (75 FR 38056). That NPRM proposed to require repetitive replacement of the upper row of fasteners (Row A) of the support fittings of the left and right engine aft mount with new fasteners. That NPRM also proposed to require repetitive general visual inspections for defects of the lower row fasteners (Row B) of the support fittings of the left and right engine aft mounts (that includes a gap check under the head or nut, and a torque check), as necessary for defects of the lower row of fasteners (Row B) of the support fittings of the left and right engine aft mounts, and replacing all clearance fit fasteners in the lower row (Row B) with new fasteners if any defect is found. Defects include missing, loose, and damaged fasteners. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public. \n\nConclusion \n\n\tWe reviewed the relevant data and determined that air safety and the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tWe estimate that this AD affects 13 airplanes of U.S. registry. \n\n\tWe estimate the following costs to comply with this AD: \n\n\t\t\t\t\tEstimated Costs\n\n\nAction\nLabor cost\nParts cost\nCost per product\nCost on U.S. operators\nReplacement\n14 work-hour X $85 per hour = $1,190\n$152 per replacement\n$1,342 per replacement cycle\n$17,446 per replacement cycle\nInspections\n4 work-hours X $85 per hour = $340\n$0\n$340 per inspection cycle\n$4,420 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 governmentand 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), \n\n\t(3) Will not affect intrastate aviation in Alaska, and \n\n\t(4) 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\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 removing airworthiness directive (AD) 2008-18-10, Amendment 39-15667 (73 FR 52203, September 9, 2008), and adding the following new AD: