COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F100 (F28 Mk 100) Series Aeroplanes AD/F100/4 Thrust Reverser Door Bumper Fittings 1/99 Applicability: F28 Mk. 100 aircraft serial numbers 11244 through 11460, 11463 through 11469, 11471, 11474, 11476, 11478 and 11479 and Grumman Aerospace part number (P/N) 1159P41440 spare aft engine cowlings, serial numbers (S/N) A0002 through A0031, S/N B0001 through B0020 (also identified as S/N 1001 through 1020) and S/N 1021 through 1220. Requirement: 1. Modify the thrust reverser doors in accordance with Fokker Service Bulletin F100- 78-010 dated 07 February 1994, and 2. Replace the Collins Multifunction Display Units (MFDUs) P/N 622-8047-412 or P/N 622-8047-422 with MFDU P/N 622-8047-414 or P/N 622-8047-423 as applicable, in accordance with Fokker SB F100-31-036 dated 07 February 1994. 3. Modify affected Grumman Aerospace spare aft cowlings P/N 115P41440 in accordance with Fokker Component SB P41440-78-02 dated 17 December 1993. Note: RLD Airworthiness Directive 94-062 (A) dated 29 April 1994 refers. Compliance: 1. Before accomplishment of 15,000 flight hours since new. 2. On completion of Requirement 1. 3. Prior to fitment to aircraft modified in accordance with Fokker SB F100-78-010 dated 07 February 1994. This Airworthiness Directive becomes effective on 28 January 1999. Background: The full scale fatigue test showed that the loads on the aircraft tail due to thrust reverser operation were higher than anticipated, resulting in a deteriorated fatigue life for the horizontal stabiliser main hinge fitting structure. This Directive is issued to reduce fatigue loads on the tail through modification of the thrust reverser doors and replacement of the multifunction display units incorporating software versions V7R1 or V8R1 as applicable.