COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes AD/AC/88 Amdt 1 Flap System 8/98 Applicability: Models 500, 500A, 500B, 500S, 500U, 520, 560, 560A, 560E, 560F, 680, 680E, 680F, 680FL, 680FL(P), 680FP, 680T, 680V, 680W, 681, 685, 690, 690A, 690B, 690C, 690D, 695, 695A, 695B, and 720 aircraft. Requirement: Perform the following in accordance with the Accomplishment Instructions section of Twin Commander Aircraft Corporation Mandatory Service Bulletin (SB) 226 or SB 226 Revision 1: 1. Inspect all flap system cable grooves for the correct width; b. Inspect all flap system pulleys for rubbing on the support brackets; c. Inspect all flap pulley cable assemblies for frayed wires; and, d. Mark pulleys that have been inspected and have the correct groove radius, with two parallel lines specified in the service bulletin. If any of the above discrepancies are found, rework or replace the affected part in accordance with SB 226 or SB 226 Revision 1. Note 1: SB 226 Revision 1 makes reference to a gauge that is available from the manufacturer for use in accomplishing the inspection. Note 2: FAA AD 98-07-17 Amdt 39-10437 refers. Compliance: Unless already accomplished, within 300 hours' time in service after 16 July 1998. This amendment becomes effective on 16 July 1998. Background: The FAA received reports of cable fatigue, particularly the master pulley cable, on several of the affected aircraft. The actions specified by this Directive are intended to prevent flap system failure, which could result in loss of control of the aircraft. Amendment 1 is issued in response to a new FAA AD which resulted from several reports of worn or frayed flap system cables attributed to flap pulley grooves that are too narrow. The original issue of this airworthiness directive became effective on 26 May 1994.