88-26-51 PRATT & WHITNEY CANADA: Amendment 39-6275. Final Rule of previously issued telegraphic AD.
Applicability: Pratt & Whitney Canada (PWC) PW115/118/118A turboprop engines prior to Serial Number (S/N) PCE 115033, and PW120/120A/121 turboprop engines prior to S/N PCE 120174.
Compliance: Required as indicated, unless already accomplished.
To prevent an uncontained engine failure resulting from low cycle fatigue failure of certain high pressure turbine (HPT) components, accomplish the following:
(a) Determine upon receipt of this AD the cyclic life accumulated on the HPT front cover, HPT rear cover, and HPT disk, in accordance with PWC Service Bulletin (SB) 20002, Revision 4, dated November 21, 1988, paragraph 2.D.(1), as follows:
(1) For engines which have not incorporated PWC SB 20133, dated September 14, 1987, calculate the total cyclic life accumulated using a flight count factor (FCF) of 1.5 in accordance with the formula found in PWC SB 20002, Revision 4, paragraph 2.D.(1).
(2) For engines which have incorporated PWC SB 20133, dated September 14, 1987, calculate the total cyclic life accumulated prior to the incorporation of PWC SB 20133 using an FCF of 1.5, plus the total cycles accumulated after the incorporation of PWC SB 20133 using an FCF of 1.0, in accordance with the note in PWC SB 20002, Revision 4, paragraph 2.D.(1).
(b) Remove from service and replace with a serviceable part within 25 cycles in service (CIS) from the receipt of this AD, those HPT front covers, HPT rear covers, or HPT disks which have accumulated 14,975 CIS or greater upon receipt of this AD, as calculated in accordance with paragraph (a)(1) or (a)(2) of this AD.
(c) Remove from service and replace with a serviceable part at or prior to accumulating 15,000 CIS, those HPT front covers, HPT rear covers, or HPT disks which have accumulated less than 14,975 CIS upon receipt of this AD, as calculated in accordance with paragraph (a)(1) or(a)(2) of this AD.
(d) Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.
(e) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance with the requirements of this AD or adjustment to the compliance times specified in this AD, may be approved by the Manager, Engine Certification Office, ANE-140, Engine and Propeller Directorate, Aircraft Certification Service, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803.
The determination of the cyclic life accumulated on the HPT front cover, HPT rear cover, and HPT disk shall be accomplished in accordance with PWC SB 20002, Revision 4, dated November 21, 1988. 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 Pratt& Whitney Canada, 1000 Marie-Victorin, Longueuil, Quebec, Canada J4G 1A1. Copies may be inspected at the Regional Rules Docket, Office of the Assistant Chief Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Room 311, Burlington, Massachusetts 01803, or at the Office of the Federal Register, 1100 L Street, Room 8301, Washington, D.C. 20591.
This amendment (39-6275, AD 88-26-51) becomes effective on September 22, 1989, as to all persons except those persons to whom it was made immediately effective by TAD T88-26-51, issued December 28, 1988, which contained this amendment.