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/26 Diffuser Case Inspection 9/94 Applicability: Pratt and Whitney JT9D-7F engines. Requirement: Action in accordance with the requirements of FAA AD 93-19-02. Compliance: Effective 18 August 1994, as specified in the FAA AD. Background: There have been reports of cracking in the diffuser case at the rear rail location.