COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Pratt and Whitney Turbine Engines - JT9D Series AD/JT9D/18 Low Pressure Turbine Airseal 3/89 Applicability: JT9D-3A,-7,-7A,-7AH, -7H, -7F, -7J, -20 engines. Requirement: Action in accordance with FAA AD 88-24-05 amdt 39-6018, items (a)(1)(2), (b), (c). Note: Subject airseals modified in accordance with the requirements of PWA SB 4835 revision 4 are considered to be in compliance with the requirements of this Directive. Compliance: 1. Airseals conforming to FAA AD 88-24-05 amdt 39-6018 item (a)(1) - Within the next 500 cycles in service after 1 March 1989. 2. Airseals conforming to FAA AD 88-24-05 amdt 39-6018 item (a)(2) - At next disassembly of the low pressure turbine module. 3. FAA AD 88-24-05 amdt 39-6018 items (b), (c) - At next disassembly of the low pressure turbine module. Background: This Directive has been issued to require modification and/or inspection of certain sixth stage low pressure turbine airseals. The Requirement follows advice that airseal rub could result in seal rupture and uncontained engine failure.