COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Fokker F27 Series Aeroplanes AD/F27/135 Nose Wheel Steering 13/93 Applicability: All F27 aircraft (except MK 050) series fitted with Walter Kidde Nose-wheel Steering System (steering unit gearbox housing assembly) P/N 893954. Requirement: Unless previously carried out, action in accordance with Fokker SB F27/32-166 dated 7 September 1993. Note: BLA AD 93-132 (A) and Fokker F27 Maintenance Circular No 32-6 refers. Compliance: Within 500 hours time in service from 1 December 1993 or by 1 February 1994, whichever occurs first. Thereafter, recheck the bolt torque value at each B-check. Background: The manufacturer has been advised of broken dowels pins in the Walter Kidde nose- wheel steering system. This has resulted in loss of directional control after touch down and in some cases the subsequent collapse of the nose gear.