COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 107 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Propellers - Variable Pitch - Dowty Rotol AD/PR/28 Amdt 1 Hub Switches 10/89 Applicability: Any Dowty Rotol Propeller P/N R193/4-30-4/xxx with the following S/N installed on Fokker F-27 aircraft. DRG 225/63, - 265/64, - 23/68, - 121/70, - 59/76, - 21/77, - 65/77, - 76/77, - 8/78, - 44/78, - 120/78, - 121/78, - 15/79, - 417/80 - 1127/80 - 3954/86. Dowty Rotol Propeller P/N R184/x-xx-x/xxx S/No DRG 118/65 installed on Gulfstream 1 G 159 aircraft. Requirement: Inspect hub switches for correct fitment, location and correct brush installation within the hub switch block. Refer Dowty Rotol Maintenance Manual 876 CM 61-2-4 Page 302/2. Note 1: Use switch P/N 601023026 in position 1 and 3 and switch P/N 601023027 in position 2. Note 2: Netherlands AD 89-19 issue 2 refers. Compliance: Unless already accomplished at next inspection for issue of a Maintenance release or by 30 October 1989 whichever occurs first. Background: Due to the possibility that the hub switches may have been incorrectly installed a one time inspection is required. Amendment 1 corrects a serial no. change.