COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F27 Series Aeroplanes AD/F27/131 Amdt 1 AN - Bolts 2/94 Applicability: Model F27 aircraft (except Mk 050), with serial numbers listed in Fokker Service Bulletin F27/51-10 Revision 2. Requirement: Accomplish the following: 1. Replace the affected eight (8) AN-bolts part number AN178-13A and four (4) AN- bolts part number AN178-26A in the nacelle brace installation (IPC Chapter 2B14300, items 15, 23, and 24) with bolts part number NAS1308-11D and part number NAS1308-34D, respectively; and replace the eight (8) AN-bolts part number AN178-26A that attach the engine mount to the nacelle firewall with bolts part number NAS1308-34D, in accordance with Engineering Modification Instruction (EMI) No. 171, as detailed in Fokker Service Bulletin F27/51-10 Revision 2. b. In the connection between the nose landing gear bracket and the forward pressure bulkhead, replace AN-bolt part number AN7-14A with bolt part number NAS1307-15D, replace AN-bolt part number AN7-16A with bolt part number NAS1307-19D, replace three AN-bolts part number AN8-16A with bolts part number NAS1308-17D, and replace AN-bolt part number AN8-17A with bolt part number NAS1308-19D, in accordance with Figure No. 7 in Fokker Service Bulletin F27/51-10 Revision 2. Note: RLD AD 91-111/2 (A) refers. Compliance: Prior to 1 January 1995. Background: A number of AN-bolts are located in places which are critical to the safety of flight. This Directive requires replacement of such bolts with bolts which are manufactured to a superior specification. Amendment 1 is issued to align with a revision of the related RLD AD which now requires the replacement of a limited number of specific AN-bolts.