AD 2000-21-06 Airworthiness Directives; Boeing Model 747 Series Airplanes Equipped with Pratt & Whitney (PW) JT9D-7Q and JT9D-7Q3 Turbofan Engines

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

Model 747 series airplanes, certificated in any category; equipped with Pratt & Whitney JT9D-7Q and JT9D-7Q3 turbofan engines. 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 (c) 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 contact between the precooler support link and the precooler support fitting, which could contribute to an uncontained failure of the diffuser case and damage to the airplane, accomplish the following: Detailed Visual Inspection (a) For any precooler support fitting having P/N 65B90924-1 or P/N 65B90924-600 that has not been reworked to the dimensions specified in Boeing Service Letter 747-SL-36-089, dated August 10, 1998: Within 6,000 hours time-in-service after the effective date of this AD, or within 18 months after the effective date of this AD, whichever occurs first, perform a detailed visual inspection to detect evidence of contact wear or contact between the precooler support fitting and link assembly, P/N 69B93162-1 or 69B93162-3, in accordance with the service letter. Rework and Reidentification (1) If no evidence of contact wear or contact between the precooler support fitting and link assembly is found: At the next engine removal, rework the precooler support fitting to the dimensions specified in the service letter, in accordance with the service letter; and permanently and legibly reidentify the support fitting as P/N 65B90924-601. (2) If any evidence of contact wear or contact between the precooler support fitting and link assembly is found: Prior to further flight, rework the precooler support fitting to the dimensions specified in the service letter, in accordance with the service letter; and permanently and legibly reidentify the support fitting as P/N 65B90924-601. Note 2: For the purposes of this AD, a detailed visual inspection is defined as: “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. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.” Reidentification (b) For any precooler support fitting having P/N 65B90924-1 or P/N 65B90924-600 that has been reworked to the dimensions specified in Boeing Service Letter 747-SL-36-089, dated August 10, 1998, but has not been permanently and legibly reidentified: Within 6,000 hours time-in-service or 18 months after the effective date of this AD, whichever occurs first, permanently and legibly reidentify the reworked fitting as P/N 65B90924-601. Alternative Methods of Compliance (c) 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 Aircraft Certification Office (ACO), FAA. 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 3: 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 (d) Special flight permits may be issued in accordance with §§ 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 (e) Except as provided by paragraphs (a)(1), (a)(2), and (b) of this AD, the actions shall be done in accordance with Boeing Service Letter 747-SL-36-089, including attachment, dated August 10, 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 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. Effective Date (f) This amendment becomes effective on November 24, 2000. Issued in Renton, Washington, on October 13, 2000. Donald L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 00-26878 Filed 10-19-00; 8:45 am] BILLING CODE 4910-13-P