AD 99-11-12 Airworthiness Directives; Boeing Model 747-400 Series Airplanes Powered by Pratt & Whitney PW4000 Engines

Models named: 747-400 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747-400 series airplanes powered by Pratt & Whitney PW4000 engines, as listed in Boeing Alert Service Bulletin 747-71A2283, dated October 10, 1996; certificated in any category. Note 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 (d) 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.

Required as indicated, unless accomplished previously. To prevent possible separation of the engine from the airplane in the event of a primary thrust linkage failure, accomplish the following: Initial Inspection and Corrective Actions (a) For Group 1 airplanes, as identified in Boeing Alert Service Bulletin 747-71A2283, dated October 10, 1996: Accomplish paragraphs (a)(1) and (a)(2), of this AD, as applicable. (1) Within 500 hours time-in-service after the effective date of this AD, perform a detailed visual inspection (Work Package 1) to ensure proper installation of the engine thrust link components, in accordance with the alert service bulletin. (i) If no attachment hardware is found loose or missing, and if no part shows signs of damage, repeat the inspection thereafter at intervals not to exceed 5,000 hours time-in-service or 15 months, whichever occurs first, until the requirements of paragraph (a)(2) of this AD have been accomplished. (ii) If any attachment hardware is found loose or missing, or if any part shows signs of damage, prior to further flight, accomplish the actions required by paragraphs (a)(1)(ii)(A) and (a)(1)(ii)(B). (A) Repair any discrepancy or damage. (B) Replace the existing end cap and end cap bolts of the forward engine mount end cap assembly with an improved end cap and end cap bolts (Work Package 2) in accordance with the alert service bulletin. Terminating Action (2) Replace the existing end cap and end cap bolts of the forward engine mount end cap assembly with an improved end cap and end cap bolts (Work Package 2), in accordance with Boeing Alert Service Bulletin 747-71A2283, dated October 10, 1996, at the earlier of the times specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. Accomplishment of the replacement constitutes terminating action for the requirements of this AD for Group 1 airplanes. (i) Prior to the accumulation of 16,000 total flight cycles on any engine, or within 500 hours time-in-service after the effective date of this AD, whichever occurs later; or (ii) Within 3 years after the effective date of this AD. (b) For Group 2 airplanes, as identified in Boeing Alert Service Bulletin 747-71A2283, dated October 10, 1996: Within 3 years after the effective date of this AD, replace the existing end cap bolts of the forward engine mount with improved end cap bolts (Work Package 3), in accordance with the alert service bulletin. Spares (c) As of the effective date of this AD, no person shall install on any airplane a forward engine mount end cap having part number 310T3026-1. Alternative Method of Compliance (d) An 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 ACO. 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. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. Special Flight Permits (e) Special 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. Incorporation by Reference (f) The inspections and replacement shall be done in accordance with Boeing Alert Service Bulletin 747-71A2283, dated October 10, 1996. 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. [[Page 28905]] (g) This amendment becomes effective on July 2, 1999. Issued in Renton, Washington, on May 20, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-13483 Filed 5-27-99; 8:45 am] BILLING CODE 4910-13-P