COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AD/B747/169 Amdt 1 Midspar Fuse Pin 9/97 Applicability: Model 747 series aircraft with line numbers 1 through 1046, equipped with Pratt and Whitney model PW4000 series engines, or General Electric model CF6-80C2 series engines, or Rolls Royce model RB211 series engines; on which fuse pins having part numbers 310U2301-101, -116, -117, or -120 ( "third generation " fuse pins ) are installed at the midspar / spring beam fittings of the engine pylon; and on which modification of the nacelle strut and wing structure in accordance with Boeing ASB 747- 54A2156 or Boeing ASB 747-54A2157, as applicable, has not been accomplished. Requirement: Inspect in accordance with the technical requirements of FAA AD 96-26-52 R1 Amdt 39-1002. Compliance: Unless the initial inspection has already been accomplished, within 15 days after 15 January 1997; thereafter as specified in the requirement document. The compliance of the initial issue of this directive remains unchanged, while the repetitive inspection frequency as specified in the new requirement document, is changed by this issue. This amendment becomes effective on 14 August 1997. Background: The FAA received a report of a fuse pin which had migrated out of an inboard spring beam fitting on the number 1 engine pylon of a model 747-400 aircraft. In addition, the mating nut to this pin had backed off from full engagement with the pin. Amendment 1 is issued in response to the issue of a new FAA AD which decreases the frequency of inspections, as a result of new data provided by the manufacturer. The original issue of this airworthiness directive became effective on 15 January 1997.