AD 2008-05-05

We are adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 series airplanes. This AD requires an inspection of the vertical fin lugs, skin, and skin edges for discrepancies; an inspection of the flight control cables, fittings, and pulleys in section 48 for signs of corrosion; an inspection of the horizontal stabilizer jackscrew, ball nut, and gimbal pins for signs of corrosion; and corrective actions if necessary. This AD results from reports indicating that moisture was found within the section 48 cavity. We are issuing this AD to ensure that the correct amount of sealant was applied around the vertical fin lugs, skin and the skin edges. Missing sealant could result in icing of the elevator cables, which could cause a system jam and corrosion of structural and flight control parts, resulting in reduced controllability of the airplane.

Final rule.

2008-05-05 Boeing: Amendment 39-15399. Docket No. FAA-2007-0202; Directorate Identifier 2007-NM-185-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective April 8, 2008. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to certain Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 series airplanes, certificated in any category; as identified in Boeing Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007. \n\nUnsafe Condition \n\n\t(d) This AD results from reports indicating that moisture was found within the section 48 cavity. We are issuing this AD to ensure that the correct amount of sealant was applied around the vertical fin lugs, skin and the skin edges. Missing sealant could result in icing of the elevator cables, which could cause a system jam and corrosion of structural and flight control parts, resulting in reduced controllability 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 \n\n\t(f) Within 2,500 flight cycles or 18 months after the effective date of this AD, whichever occurs first, do the detailed inspections specified in paragraphs (f)(1), (f)(2), and (f)(3) of this AD in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007. \n\n\t(1) Do a detailed inspection of the vertical fin lugs, skin, and skin edges for discrepancies (i.e., water ingress; corrosion damage; and missing, insufficient, or cracked sealant). \n\t(2) Do a detailed inspection of the flight control cables, fittings, and pulleys in section 48 for signs of corrosion. \n\t(3) Do a detailed inspection of the horizontal stabilizer jackscrew, ball nut, and gimbal pins for signs of corrosion. \n\n\tNote 1: For the purposes of this AD, a detailed inspection is: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector (i.e., the person performing the inspection). Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.'' \n\nCorrective Actions \n\n\t(g) If any discrepancy or corrosion is found during any inspection required by paragraph (f) of this AD, before further flight, do the applicable corrective actions in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007; except where the service bulletin specifies to contact Boeing, repair using a method approved in accordance with the procedures specified in paragraph (i) of this AD. \n\nCredit for Actions Done Using the Previous Service Information \n\n\t(h) Actions accomplished before the effective date of this AD in accordance with Boeing Service Bulletin 737-53A1242, dated October 17, 2002; or Revision 1, dated April 28, 2005; are considered acceptable for compliance with the corresponding actions specified in paragraphs (f) and (g) of this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(i)(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\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\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(j) You must use Boeing Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007, 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\t(2) For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. \n\t(3) You may review copies of the service information incorporated by reference 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/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 certain Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 series airplanes. That NPRM was published in the Federal Register on November 19, 2007 (72 FR 64955). That NPRM proposed to require an inspection of the vertical fin lugs, skin, and skin edges for discrepancies; an inspection of the flight control cables, fittings, and pulleys in section 48 for signs of corrosion; an inspection of the horizontal stabilizer jackscrew, ball nut, and gimbal pins for signs of corrosion; and corrective actions if necessary. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We considered the comment received. Boeing, the single commenter, supports the NPRM. \n\nConclusion \n\n\tWe reviewed the relevant data, considered the comment received, and determined that air safetyand the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tThere are 829 airplanes of the affected design in the worldwide fleet. This AD affects about 372 airplanes of U.S. registry. The required actions take about 1 work hour per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of this AD for U.S. operators is $29,760, or $80 per airplane. \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 \nsection, 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\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.You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \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 adding the following new AD: