98-24-26: Leading Edge Flaps

98-24-26 BOEING: Amendment 39-10913. Docket 97-NM-13-AD. \n\n\tApplicability: Model 747-400 series airplanes, line positions 696 through 1090 inclusive; 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 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.To prevent uncommanded automatic retraction of the leading edge flaps during takeoff, which would seriously degrade liftoff and climb capabilities, and could result in near-stall conditions, accomplish the following: \n\n\t(a)\tWithin 18 months after the effective date of this AD, accomplish the requirements of paragraph (a)(1) or (a)(2) of this AD, as applicable, in accordance with Boeing Service Bulletin 747-27A2356, Revision 1, dated August 13, 1998. \n\n\t\t(1)\tFor Groups 1 and 2 airplanes, as listed in the service bulletin: Replace the cam assembly, cam bellcrank assembly, and thrust reverser control switch actuator on all four thrust levers with new components. \n\n\t\t(2)\tFor Groups 3 and 4 airplanes, as listed in the service bulletin: Replace the cam bellcrank assembly and thrust reverser control switch actuator on all four thrust levers with new components. \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. \n\n\t(d)\tThe actions shall be done in accordance with Boeing Service Bulletin 747-27A2356, Revision 1, dated August 13, 1998. 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 BoeingCommercial 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 December 30, 1998.