COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Propellers - Variable Pitch - Hamilton Standard AD/PHS/11 Amdt 1 Blade Retaining Rings 13/88 Applicability: All Model 14SF-5 and 14SF-7 propellers fitted to, but not limited to, De Havilland Dash 8 and Aerospatiale ATR 42 aircraft. Requirement: 1. Inspect the plastic "Rynite" blade retaining rings on all four blades in accordance with Hamilton Standard Alert Service Bulletin 14SF-61-A21 Revision 2. Blade retaining rings with evidence of cracks require removal of both halves from service before further flight and replacement with new retaining ring halves in accordance with ASB 14SF-61-A21 Revision 2. 2. Replace the plastic "Rynite" blade retaining rings P/N 785540 with aluminium blade retaining rings P/N 794345 on all four blades, in accordance with Hamilton Standard SB 14SF-61-17 Revision 1. Note: FAA AD 88-20-08 Amdt 39-6009 refers. Compliance: 1. Inspect within 50 hours time in service after 22 June 1987 and thereafter at intervals not exceeding 200 hours time in service. 2. Prior to 31 July 1989. Background: Loss of the plastic "Rynite" retaining ring may cause severe damage to the blade retention system caused by the subsequent propeller vibration. This Amendment is raised to introduce terminating action.