AD 91-01-03

91-01-03 PRATT & WHITNEY CANADA: Amendment 39-6843. Docket No. 90-ANE-38-AD. Applicability: Pratt & Whitney Canada (PWC) PW118, PW118A, PW120, PW120A, PW121, and JT15D- 5 model engines, installed on, but not limited to, DeHavilland of Canada DHC-8 Series 100, Embraer EMB120, Aerospatiale ATR-42, Beech Beechjet, Cessna T47A, and Siai-Marchetti S211 aircraft. Compliance: Required as indicated, unless already accomplished. To prevent a fire hazard in the engine nacelle, accomplish the following: (a) For engines equipped with Hamilton-Standard Model JFC118 hydromechanical fuel control units (HMU) identified in Table I of this AD, excluding HMU's marked "MS090-001", perform the following: (1) Perform an HMU leak check inspection in accordance with the applicable Accomplishment Instructions of Appendix I of this AD, within the next 15 hours time in service after the effective date of this AD. (2) Thereafter, reinspect the HMU for leakage in accordance with the applicable Accomplishment Instructions of Appendix I at intervals not to exceed 15 hours time in service since last inspection. (3) Remove from service, prior to further flight, HMU's exhibiting fuel leakage when inspected in accordance with (a)(1) or (a)(2) above. (4) X-ray or disassemble inspect the HMU for correct assembly in accordance with the Accomplishment Instructions of the applicable Hamilton-Standard (HS) service bulletin (SB) listed in Table I of this AD, at the next engine shop visit or HMU removal, or by June 30, 1991, whichever occurs first. (5) Remove from service, prior to further flight, HMU's confirmed incorrectly assembled when inspected in accordance with (a)(4) above. (6) For HMU's determined to be correctly assembled when inspected in accordance with (a)(4) above, the repetitive inspections of (a)(1) or (a)(2) above are no longer required.

Table I

HMU Model/P/N(s) JFC118-10/786390-3 HS SB JFC118-10-73-14, Revision 1 (Oct. 26, 1990) JFC118-11/786391-3 and 786391-5 JFC118-11-73-15, Revision 1 (Oct. 26, 1990) JFC118-12/786392-4 and 786392-6 JFC118-12-73-16, Revision 1(Oct. 26, 1990) JFC118-30/787230-1 JFC118-30-73-15, Revision 1 (Oct 26, 1990) JFC118-31/776660-3 and 790155-1 JFC118-31-73-14, Revision 1 (Oct. 26, 1990)

(b) For the purpose of this AD, shop visit is defined as the induction of an engine into a shop for the conduct of maintenance. (c) 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. (d) 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 adjustments to the compliance schedule specified in this AD may be approved by the Manager, Engine Certification Office, ANE-140, Engine and Propeller Directorate, Aircraft Certification Service, FAA, 12 New England Executive Park, Burlington, Massachusetts01803. The x-ray and disassembly inspection shall be done in accordance with the following HS documents:

Document Page Revision Date HS SB JFC118-10-73-14 All 1 Oct. 26, 1990 HS SB JFC118-11-73-15 All 1 Oct. 26, 1990 HS SB JFC118-12-73-16 All 1 Oct. 26, 1990 HS SB JFC118-30-73-15 All 1 Oct. 26, 1990 HS SB JFC118-31-73-14 All 1 Oct. 26, 1990

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 the United Technologies Corporation, Hamilton-Standard Division, Technical Publications Department, One Hamilton Road, Windsor Locks, Connecticut 06096-1010. 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 01803, or at the office of the Federal Register, 1100 L Street, NW, Room 8401, Washington, D.C. 20591. This amendment (39-6843, AD 91-01-03) becomes effective on January 07, 1991.

APPENDIX I

PART A: PW100 SERIES A. References: - Models PW118 (BS698)/PW118A (BS718): Maintenance Manual P/N 3034622. - Models PW120 (BS633/BS716) and PW121 (BS722/BS725): Maintenance Manual P/N 3034642. - Models PW120A (BS632) and PW121 (BS717): Maintenance Manual P/N 3034632. B. Accomplishment Instructions: Perform the following HMU leak check inspection. 1.) Perform a fuel system leak test in accordance with the applicable maintenance manual, or visually inspect the HMU for external fuel leaks within 30 minutes of shutdown. 2.) Ensure there is no fuel leakage at the HMU electrical connector area. 3.) If any fuel leak is observed, remove the HMU from service. 4.) Annotate engine log to include this AD inspection. NOTE: Information concerning this inspection can be found in Pratt & Whitney Canada (PWC) Service Bulletin (SB) No. 20951.

PART B: JT15D SERIES A. References: -Model JT15D-5: Maintenance Manual P/N 3033442 B. Accomplishment Instructions: Perform the following HMU leak check inspection. 1.) Perform a fuel system leak test in accordance with the applicable maintenance manual, or visually inspect the HMU for external fuel leaks within 30 minutes of shutdown. 2.) Ensure there is no fuel leakage at the HMU electrical connector area. 3.) If any fuel leak is observed, remove the HMU from service. 4.) Annotate engine log to include this AD inspection. NOTE: Information concerning this inspection can be found in PWC SB No. A-7295.