AD 92-01-08 ACTIVE

92-01-08 PRATT & WHITNEY CANADA: Amendment 39-8132. Docket No. 90-ANE-29.
Applicability: Pratt & Whitney Canada (PWC) PW115, PW118, PW118A, PW120, PW120A, PW121, PW123, PW124B, and PW125B model turboprop engines, with specific engine serial numbers noted in the applicable service bulletins (SB). Affected engines are installed in, but not limited to, the Aerospatiale ATR-42, and ATR-72, British Aerospace ATP, DeHavilland of Canada DHC-8, Embraer EMB-120, Canadair CL-215T, and Fokker 50 aircraft.
Compliance: Required at the next engine module overhaul, hot section inspection (HSI), or within 36 months from the effective date of this airworthiness directive (AD), whichever occurs first, unless accomplished previously.
To prevent seizure of the high pressure rotor, and subsequent inability to restart the engine inflight, accomplish the following:
(a) Rework or replace with a serviceable part, the high pressure turbine front cover in accordance with the requirements of anyof the following PWC SBs, as applicable: SB 20417, Revision 2, dated August 20, 1990, SB 20412, dated November 27, 1989; SB 20604, Revision 1, dated February 25, 1991; or SB 20979, dated April 29, 1991.
(b) Rework the low pressure turbine stator vane assembly in accordance with the requirements of PWC SB 20456, Revision 3, dated August 20, 1990.
(c) For engines incorporating the "triple segmented" high pressure vane ring segment assembly, Part Number (P/N) 3037761, rework or replace the high pressure vane segments as follows:
(1) For PW115, PW118, PW120, PW120A, and PW121 model turboprop engines, rework or replace with a serviceable part in accordance with the requirements of either of the following PWC SBs, as applicable: SB 20419, Revision 3, dated November 26, 1990; or SB 20886, Revision 2, dated February 11, 1991.
(2) For PW118A, PW123, PW124B, and PW125B model turboprop engines, rework or replace with a serviceable part in accordance with the requirements of any of the following PWC SBs, as applicable: SB 20419, Revision 3, dated November 26, 1990; SB 20726, dated February 19, 1990; SB 20742, Revision 4, dated June 12, 1991; SB 20886, Revision 2, dated February 11, 1991; or SB 20869, Revision 1, dated April 26, 1991.
(d) For engines incorporating the "triple segmented" high pressure vane ring segment assembly, P/N 3037761, rework or replace with a serviceable part, the cooling air nozzle housing assembly as follows:
(1) For PW115, PW118, PW120, PW120A, and PW121 model turboprop engines, rework or replace with a serviceable part in accordance with the requirements of any of the following PWC SB's, as applicable: SB 20341, Revision 2, dated September 3, 1991, SB 20436, dated March 6, 1989, or SB 20873, Revision 3, dated April 8, 1991.
(2) For PW118A, PW123, PW124B, and PW125B model turboprop engines, rework or replace with a serviceable part in accordance with the requirements of any of the following PWC SB's, as applicable: SB 20341, Revision 2, dated September 3, 1991, SB 20436, dated March 6, 1989, SB 20873, Revision 3, dated April 8, 1991, SB 20896, Revision 3, dated August 26, 1991, or SB 20872, Revision 2, dated July 8, 1991.
(e) 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, Engine Certification Office, Engine and Propeller Directorate. The request should be forwarded through an FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(f) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.
(g) The engine modifications shallbe done in accordance with the following Pratt & Whitney Canada SB's:

DOCUMENT NO.
PAGE
ISSUE/REVISION
DATE
SB 20341R2
1-4
Rev. 2
Sept. 3, 1991
Total Pages: 4

SB 20412
1-8
Original
Nov. 27, 1989
Total Pages: 8

SB 20417R2
1-7
Rev. 2
Aug. 20, 1990
Total Pages: 7

SB 20419R3
1-6
Rev. 3
Nov. 26, 1990
Total Pages: 6

SB 20436
1-3
Original
Mar. 6, 1989
Total Pages: 3

SB 20456R3
1-3
Rev. 3
Aug. 20, 1990

4
Rev. 1
Oct. 12, 1989

5
Rev. 2
Apr. 30, 1990

6-8
Original
Jun. 21, 1989
Total Pages: 8

SB 20604R1
1-7
Rev. 1
Feb. 25, 1991
Total Pages: 7

SB 20726
1-3
Original
Feb. 19, 1990
Total Pages: 3

SB 20742R4
1-4
Rev. 4
June 17, 1991
Total Pages: 4

SB 20869R1
1-6
Rev. 1
Apr. 26, 1991
Total Pages: 6

SB 20872R2
1-30
Rev. 2
July 8, 1991
Total Pages: 30

SB 20873R3
1-7
Rev. 3
Apr. 8, 1991
Total Pages: 7

SB 20886R21-6
Rev. 2
Feb. 11, 1991
Total Pages: 6

SB 20896R3
1-9
Rev. 3
Aug. 26, 1991
Total Pages: 9

SB 20979
1-7
Original
Apr. 29, 1991
Total Pages: 7

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, Technical Publications Department, 1000 Marie Victorin, Longueuil, Quebec J4G 1A1. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Room 311, Burlington, Massachusetts, or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C.
(h) This amendment becomes effective on July 27, 1992.