COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Pratt and Whitney Turbine Engines - JT8D Series AD/JT8D/24 Amdt 1 Seventh Stage Compressor Airseal 2/90 Applicability: JT8D-1, -1A, -1B, -7, -7A, -7B,-9, -9A, -11, -15, -17, -17R engines not incorporating PWA SB No. 5738. Requirement: 1. Inspect the seventh stage airseal for evidence of corrosion and/or cracking. 2. Action in accordance with PWA SB No. 5738. Compliance: 1. At next scheduled engine shop visit which requires disassembly of the engine at any flange other than the fan case or thrust reverser, and thereafter at intervals not to exceed 8,000 cycles. 2. (a) For engines with an aircraft fleet annual utilisation of 500 cycles or greater, at next disassembly of the high compressor from the diffuser case. (b) For engines with an aircraft fleet annual utilisation of less than 500 cycles, at next engine shop visit, but no later than 31 December 1990. Effective: 22 February 1990. Background: This Directive has been amended to alleviate the original calendar compliance requirement, and to reflect advice received from the manufacturer. The Directive now requires repetitive inspections of pre SB No. 5738 airseals until incorporation of SB No. 5738.