88-03-01 PRATT & WHITNEY CANADA: Amendment 39-6032. Final copy of priority letter AD issued February 2, 1988. Applies to Pratt & Whitney Canada (PWC) PT6B-36A turboshaft engines incorporating the third stage compressor stator assembly, Part Number (P/N) 3109163-01, installed in Sikorsky Aircraft S-76B helicopters. The third stage compressor stator assembly, P/N 3109163-01 is incorporated in engines, Serial Number PC-E36043 and subsequent, and those engines incorporating PWC Service Bulletin (SB) 11022, dated September 28, 1987.
Compliance is required as indicated, unless already accomplished.
To prevent failure of the third stage compressor stator vane assembly which could result in loss of engine power or an inflight engine shutdown, accomplish the following:
(a) Prior to further flight, accomplish the following:
(1) Attach a placard which reads "avoid N1 ranges, 78-80.5 percent, 95.6-97.6 percent", in full view of the pilot and copilot, as close as practicable to the N1 speed indicators.
(2) Place a copy of this AD in the appropriate rotorcraft flight manual.
(3) Operate the rotorcraft in accordance with these speed range restrictions.
(b) For engines which have accumulated 25 hours or less total time in service (TIS) from the effective date of this AD, accomplish the following:
(1) Install vibration damping device, Part Number (P/N) 3112128-01, on vane assembly, P/N 3109163-01, in accordance with PWC Alert SB A-11033, dated December 31, 1987, prior to accumulating 25 hours total TIS.
(2) Remove vane assembly, P/N 3109163-01, prior to accumulating 600 hours total TIS, and replace with a serviceable part.
(c) For engines which have accumulated more than 25 hours total TIS from the effective date of this AD, accomplish the following:
(1) Install vibration damping device, P/N 3112128-01, on vane assembly, P/N 3109163-01, in accordance with PWC Alert SB A-11033, dated December 31, 1987, within 25 hours TIS from the effectivedate of this AD.
(2) Remove vane assembly, P/N 3109163-01, within 100 hours TIS from the installation of damping device, P/N 3112128-01, and replace with a serviceable part.
(d) Thereafter, remove from service vane assembly, P/N 3109163-01, prior to accumulating 600 hours TIS since new, and replace with a serviceable part.
NOTE: When vane assembly, P/N 3109163-01, is installed as a serviceable part, it must include damping device, P/N 3112128-01.
(e) Aircraft may be ferried in accordance with the provisions of Federal Aviation Regulations 21.197 and 21.199 to a base where the AD can be accomplished.
(f) Upon request from an operator, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Engine Certification Office, Engine & Propeller Directorate, Aircraft Certification Service.
(g) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, the Manager, Engine Certification Office, Engine & Propeller Directorate, Aircraft Certification Service, may adjust the compliance time specified in this AD.
PWC Alert SB 11033, dated December 31, 1987, and PWC SB 11022, dated September 28, 1987, identified and described in this document, are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Pratt & Whitney Canada, Box 10, Longueuil, Quebec, Canada J4K 4X9. These documents may also be examined at the Office of the Assistant Chief Counsel, Federal Aviation Administration, New England Region, Rules Docket No. 88-ANE-06, 12 New England Executive Park, Burlington, Massachusetts 01803, Room 311.
This amendment, 39-6032, becomes effective November 29, 1988, as to all persons except those persons to whom it was made immediately effective by individual priority letter AD 88-03-01, issued February 2, 1988, which contained this amendment.