AD 2005-06-09 ACTIVE

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747-200B, 747-200C, 747-200F, 747-300, and 747SR series airplanes, equipped with GE CF6-45 or -50 series engines. This AD requires modifying the side cowl assemblies on the engines by replacing existing wear plates with new extended wear plates and installing new stop fittings. This AD is prompted by reports of a gap at the interface of the lower portion of the side cowl and the aft flange of the thrust reverser. We are issuing this AD to prevent an excessive quantity of air from entering the fire zone that surrounds the engine, which, in the event of an engine fire, could result in an inability to control or extinguish the fire.

Final rule.

2005-06-09 Boeing: Amendment 39-14017. Docket No. FAA-2004-19945; Directorate Identifier 2004-NM-22-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective April 25, 2005. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to Boeing Model 747-200B, 747-200C, 747- 200F, 747-300, and 747SR series airplanes; certificated in any category; equipped with General Electric CF6-45 or -50 series engines. \n\nUnsafe Condition \n\n\t(d) This AD was prompted by reports of a gap at the interface of the lower portion of the side cowl and the aft flange of the thrust reverser. We are issuing this AD to prevent an excessive quantity of air from entering the fire zone that surrounds the engine, which, in the event of an engine fire, could result in an inability to control or extinguish the fire. \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\nModification \n\n\t(f) Within 24 months after the effective date of this AD: Modify the side cowl assemblies on the engines by replacing existing wear plates with new extended wear plates and installing new stop fittings, by doing all actions according to the Accomplishment Instructions of Boeing Service Bulletin 747-71-2300, Revision 1, dated October 30, 2003. Any applicable corrective actions must be done before further flight. \n\nOn Condition: Removal of Bulb Seals and Other Specified Actions \n\n\t(g) If bulb seals were installed on the trailing edge of the fan thrust reverser in accordance with Boeing Service Letter 747-SL-71- 045: Concurrently with or before further flight after accomplishing paragraph (f) of this AD, remove the bulb seals, plug the open holes in the trailing edge of the fan thrust reverser, and adjust the cowl latches as applicable, in accordance with Boeing Service Letter 747- SL-71-045-C, dated April 10, 2003. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(h) 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\nMaterial Incorporated by Reference \n\n\t(i) You must use Boeing Service Bulletin 747-71-2300, Revision 1, dated October 30, 2003; and Boeing Service Letter 747-SL-71-045- C, including Attachment, dated April 10, 2003; as applicable, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approves the incorporation by reference of those documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. For copies of the service information, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. For information on the availability of this material at the National Archives and Records Administration (NARA), call (202) 741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. \n\n\tYou may view the AD docket at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Nassif Building, Washington, DC.

The FAA proposed to amend 14 CFR Part 39 with an AD for certain Boeing Model 747-200B, 747-200C, 747-200F, 747- 300, and 747SR series airplanes, equipped with General Electric CF6-45 or -50 series engines. That action, published in the Federal Register on January 3, 2005 (70 FR 51), proposed to require modifying the side cowl assemblies on the engines by replacing existing wear plates with new extended wear plates and installing new stop fittings. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the single comment that has been submitted on the proposed AD. The commenter supports the proposed AD. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comment that has been submitted, and determined that air safety and the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tThere are about 140 airplanes of the affected design in the worldwide fleet. This AD affects about 38 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\nAction \nWork hours \nAverage labor rate per hour \nParts \nCost per airplane \nFleet cost \nModification per Boeing Service Bulletin 747-71-2300, Revision 1 \n72 \n$65 \n$25,736 \n$30,416 \n$1,155,808 \n\nAuthority for This Rulemaking \n\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\t(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under thecriteria of the Regulatory Flexibility Act. \n\n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD. 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 FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD):

For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. \n\n\tDocket: The AD docket contains the proposed AD, comments, and any final disposition. You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647- 5227) is located on the plaza level of the Nassif Building at the U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Washington, DC. This docket number is FAA-2004-19945; the directorate identifier for this docket is 2004-NM-22-AD.

Dan Kinney, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6499; fax (425) 917-6590.