AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section. Piper PA-23 (Apache and Aztec) Series Aeroplanes AD/PA-23/89 Flap Control Torque Tube 8/2003 Applicability: Model PA-23 and PA-23-160 aircraft, serial numbers 23-1 through 23-2046. Model PA-23-235 aircraft, serial numbers 27-505 through 27-622. Model PA-23-250 aircraft, serial numbers 27-1 through 27-504, and 27-2000 through 27-8154030. Model PA-E23-250 aircraft, serial numbers 27-2505 through 27-4916, and 27- 7304917 through 27-7554168. Requirement: Inspect the flap control torque tube for cracks, corrosion, wear, or elongation of the attachment bolt holes (referred to as damage); in accordance with sections 3 through 10 of the Accomplishment Instructions section of Piper Mandatory Service Bulletin No. 1051B, dated 5 November 2002. Replace, before further flight after the inspection where damage is found, any damaged flap control tube, and any wooden end plugs with new plastic end plugs part number 17631-002. Replace the flap control tubes with either a part number 17634- 002 flap control torque tube or a part number 104622-002 or 104622-004 flap control torque tube assembly. The part number 17631-002 end plugs are part of the part number 104622-002 and 104622-004 flap control torque tube assemblies, but must be obtained for the part number 17634-002 installation. Note: FAA AD 2003-09-13 Amdt 39-13142 refers. Compliance: Initially inspect upon accumulating 2,500 hours time in service on the flap control torque tube or within 100 hours time in service after 7 August 2003, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 500 hours time in service; until a replacement flap control torque tube or flap control torque tube assembly as specified in the Requirement part of this Directive, is installed. This Airworthiness Directive becomes effective on 7 August 2003. Piper PA-23 (Apache and Aztec) Series Aeroplanes AD/PA-23/89 (continued) Background: The FAA received several reports of damage found in the flap control torque tube on the affected aircraft. Undetected damage to the flap control torque tube could result in failure of the flap operating system. David Punshon Delegate of the Civil Aviation Safety Authority 26 June 2003 The above AD is notified in the Commonwealth of Australia Gazette on 16 July 2003.