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/14 Amdt 1 Diffuser Case Rear Rail Cracking 6/93 Applicability: JT9D-7, 7A, -7H, -7AH, -7F, -7J. Requirement: Inspect the diffuser case rear rail for cracking in accordance with Pratt and Whitney Service Bulletin 5591 Revision 7. Note: FAA AD 86-11-04 refers. Compliance: Effective 27 May 1993: As detailed in the requirement document. Background: This Directive has been amended to reflect the manufacturer's latest revision to the requirement document. The revision, in part, introduces a new Eddy Current Inspection (ECI) probe and reduced inspection intervals for diffuser cases with weld repairs in certain locations and various crack lengths.