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/25 Fan Blade Inspection/Revised Shroud Angle 8/94 Applicability: All JT9D-7R4 Series engines. Requirement: 1. Inspect fan blade leading edges in accordance with Pratt and Whitney Service Bulletin 72-255 Revision 5. 2. Incorporate fan blades featuring a revised shroud angle in accordance with Pratt and Whitney Service Bulletin 72-309 Revision 10. Incorporation of Pratt and Whitney Service Bulletin 72-309 Rev 10 constitutes terminating action for the repetitive inspection per Requirement 1. Note: FAA AD 94-08-06 also refers. Compliance: 1. Initially within 200 cycles in service from 21 July 1994, and thereafter, at intervals not to exceed 200 cycles. 2. No later than 21 July 1996. Background: This Directive is issued to prevent fan blade failures that have been attributed to a combination of high vibratory stresses and foreign object damage.