COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fuel Supply and Metering Equipment AD/FSM/28 Hamilton Standard JFC118 Fuel Leak Inspection 13/90 TX Applicability: Hamilton Standard hydro-mechanical units (HMU) fitted to Pratt and Whitney Canada PW115, PW118, PW118A, PW120, PW120A, PW121 and JT15D-4C engines, as listed in Hamilton Standard Service Bulletins: JFC118-10-73-14 R1, JFC118-11-73-15 R1, JFC118-12-73-16 R1, JFC118-30-73-15 R1, JFC118-31-73-14 R1. Requirement: 1. Inspect the HMU for evidence of fuel leakage as detailed in the applicable engine Maintenance Manual, or Overhaul Manual, or visually inspect the HMU for fuel leakage within 30 minutes of engine shutdown. 2. Replace HMU with a HMU which has been inspected or repaired by Hamilton Standard and identified with MSO ?90-001?, or a once only internal inspection of the applicable HMU, and if required, replacement of torque motor transfer tube packing and back up retainer ring in accordance with the applicable Service Bulletin. Note: Transport Canada AD CF90-24 R1 refers. Compliance: Effective 30 October 1990: 1. Within 10 flight hours, and thereafter at intervals not to exceed 10 flight hours until compliance with Requirement 2. 2. At next engine shop visit. Background: This Directive has been issued to require inspection of certain Hamilton Standard HMUs as fitted to certain PW100 and JT15D series engines. The Requirement follows advice that incorrect assembly of an internal seal may result in fuel leakage from the HMU.