COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F28 Series Aeroplanes AD/F28/24C Cargo Doors - Door Lock NK Mechanism - Inspection and Modification Applicability: All models with S/Nos. 11003 to 11993. Requirement: 1. Inspect door locking mechanism as per Part 2 of SB F28/52-53 by aircraft S/No. as referenced in applicable SB. 2. Modify door locking mechanism by fitting a reinforced safety catch and stop assembly, detailed in SB F28/52-51 on aircraft with S/nos. referenced in that service bulletin. 3. Further modify door locking mechanism by fitting a revised switch operating mechanism as detailed in SB F28/52-49 on aircraft with S/No. referenced in that service bulletin. 4. Further modify the cargo door locking mechanism by reinforcing the door locking handle access panel as detailed in SB F28/52-81 on aircraft with S/Nos. and cargo door configurations referenced in that SB. RLD AD A118/77 also refers. Compliance: For Para. 1 - Before 1 September 1974. For Para. 2 - Before 1 January 1975. For Para. 3 - Before 1 January 1975. For Para. 4 - Before 15 July 1978.