AD 96-08-05

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 series airplanes, that requires modification of the engine fuel feed system. This amendment is prompted by reports indicating that the coupling nut on the fuel tube on the outboard strut (engine position 1) fractured. The actions specified by this AD are intended to prevent such fracturing of the coupling nut, which could result in release of fuel onto the engine cowling and a subsequent fire.

Final rule

96-08-05 BOEING: Amendment 39-9571. Docket 95-NM-98-AD. \n\n\tApplicability: Model 747-400 series airplanes powered by General Electric CF6-80C2 or Pratt & Whitney PW4000 series engines; as identified in Boeing Alert Service Bulletin 747-28A2185, Revision 1, dated September 21, 1995, and Boeing Service Bulletin 747-28-2146, dated August 13, 1992; certificated in any category. \n\n\tNOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent fracturing of the coupling nut, which could result in release of fuel onto the engine cowling and a subsequent fire, accomplish the following: \n\n\t(a)\tWithin 24 months after the effective date of this AD, accomplish the requirements of paragraph (a)(1) or (a)(2), as applicable.\n \n\t\t(1)\tFor Model 747-400 series airplanes identified in Boeing Alert Service Bulletin 747-28A2185, Revision 1, dated September 21, 1995: Replace the strut fuel tubes and couplings at engine numbers 1 and 4 with new redesigned (shrouded) couplings, in accordance with that alert service bulletin. \n\n\t\t(2)\tFor Model 747-400 series airplanes having variable numbers RT641 through RT650 inclusive, identified in Boeing Service Bulletin 747-28-2146, dated August 13, 1992: On engine positions 1 and 4 only, install new fuel lines, shrouded fuel line couplings (between the strut mid bulkhead and the wing front spar), and drain lines in accordance with that service bulletin. \n\n\t(b)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. \n\n\tNOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\t(c)\tSpecial flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.(d)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 747- 28A2185, Revision 1, dated September 21, 1995, and Boeing Service Bulletin 747-28-2146, dated August 13, 1992. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(e)\tThis amendment becomes effective on May 23, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 series airplanes was published in the Federal Register on December 12, 1995 (60 FR 63663). That action proposed to require modification of the engine fuel feed system. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\n\tOne commenter supports the proposed rule. \n\n\tThe Air Transport Association (ATA) of America, on behalf of one of its members, requests that the proposed compliance time be extended from 18 months to 24 months to provide time for operators to procure replacement kits and to accomplish the proposed actions during a regularly scheduled maintenance ("C") check. The FAA concurs with the commenter's request. The FAA finds that extending the compliance time to 24 months will not compromise safety; will allow operators sufficient time to procure the necessary replacement kits (estimated by the manufacturer to take approximately nine months); and will allow the modification to be accomplished during a "C" check interval (15 months for most operators) at a main maintenance base where special equipment and trained personnel will be available if necessary. \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\n\tThere are approximately 226 Model 747-400 series airplanes of the affected design in the worldwide fleet. \n\n\tThe FAA estimates that 34 airplanes of U.S. registry will be required by this AD to replace the strut fuel tubes and couplingsat engine positions 1 and 4 in accordance with Boeing Alert Service Bulletin 747-28A2185. That replacement will take approximately 74 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $9,582 per airplane. Based on these figures, the cost impact of this required replacement on U.S. operators is estimated to be $476,748, or $14,022 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. \n\n\tCurrently, there are no Model 747-400 series airplanes on the U.S. Register that would be required by this AD to accomplish the installation specified in Boeing Service Bulletin 747-28-2146 (and required by paragraph (a)(2) of the final rule). However, should an affected airplane be imported and placed on the U.S. Registerin the future, it would require approximately 162 work hours per airplane (81 work hours per engine; 2 engines per airplane) to accomplish the installation, at an average labor rate of $60 per work hour. Required parts would cost approximately $9,582 per airplane. Based on these figures, the cost impact of this installation would be $19,302 per airplane. \n\n\tThe regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT RegulatoryPolicies and Procedures (44 FR 11034, February 26, 1979); and (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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."\n\n List of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 USC 106(g), 40113, 44701. § 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: