AD 2009-13-08

We are adopting a new airworthiness directive (AD) for all McDonnell Douglas Model MD-90-30 airplanes. This AD requires repetitive inspections for cracks of the upper aft skin panels on the horizontal stabilizer, and related investigative and corrective actions if necessary. This AD results from a report of cracks found in the aft skin panels on the upper right side of the horizontal stabilizer at the aft inboard corner. We are issuing this AD to detect and correct cracks in the fail-safe structure that may not be able to sustain limit load, which could result in the loss of overall structural integrity of the horizontal stabilizer.

Final rule.

2009-13-08 McDonnell Douglas: Amendment 39-15947. Docket No. FAA- 2009-0160; Directorate Identifier 2008-NM-176-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective August 3, 2009. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to all McDonnell Douglas Model MD-90-30 airplanes, certificated in any category. \n\nSubject \n\n\t(d) Air Transport Association (ATA) of America Code 55: Stabilizers. \n\nUnsafe Condition \n\n\t(e) This AD results from a report of cracks found in the right upper aft skin panel of the horizontal stabilizer at the aft inboard corner. We are issuing this AD to detect and correct cracks in the fail-safe structure that may not be able to sustain limit load, which could result in the loss of overall structural integrity of the horizontal stabilizer. \n\nCompliance \n\n\t(f) Comply with this AD within the compliance times specified, unless already done. \n\nInspections \n\n\t(g) Except as required by paragraphs (h) and (i) of this AD: At the times specified in paragraph 1.E., "Compliance,'' of Boeing Alert Service Bulletin MD90-55A012, dated September 23, 2008, do an eddy current inspection for cracks of the upper aft skin panels on the left and right sides of the horizontal stabilizer, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of the service bulletin. \n\nExceptions to Service Bulletin Specifications \n\n\t(h) Where Boeing Alert Service Bulletin MD90-55A012, dated September 23, 2008, 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\t(i) If any crack is found during any inspection required by this AD, and Boeing Alert Service Bulletin MD90-55A012, dated September 23, 2008, specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (k) of this AD. \n\nInspections Done According to Multiple Operator Message \n\n\t(j) Inspections and corrective actions done before the effective date of this AD are acceptable for compliance with the corresponding requirements of this AD, if done in accordance with Boeing Multiple Operator Message 1-669017091-1, dated November 9, 2007. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(k)(1) The Manager, Los Angeles Aircraft Certification Office, FAA, ATTN: Roger Durbin, Aerospace Engineer, Airframe Branch, ANM- 120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627- 5233; fax (562) 627-5210; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. \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 towhich the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, in the FAA Flight Standards District Office (FSDO), or lacking a principal inspector, your local FSDO. 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, 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 the approval must specifically refer to this AD. \n\nMaterial Incorporated by Reference \n\n\t(l) You must use Boeing Alert Service Bulletin MD90-55A012, dated September 23, 2008, 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 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, 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\t(3) You may review 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\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 McDonnell Douglas Model MD-90-30 airplanes. That NPRM was published in the Federal Register on March 23, 2009 (74 FR 12100). That NPRM proposed to require repetitive inspections for cracks of the upper aft skin panels on the horizontal stabilizer, 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 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 16 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tEstimated Costs \n\n\n\nAction\nWork hours\nAverage labor rate per hour\nParts\nCost per airplane\nNumber of U.S.-registered airplanes\nFleet cost\nInspection\n4\n$80\nNone\n$320 per inspection cycle\n16\n$5,120 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\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, (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\tYou can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \n\nList of Subjects in 14 CFR Part 39Air 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: