COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 180, 182 and Wren 460 Series Aeroplanes AD/CESSNA 180/79 Wing Lower Spar Cap Angle Stiffener 12/98 Applicability: The following aircraft models, all serial numbers, that have wing extension supplemental type certificate (STC) SA00276NY or supplemental type approval (STA) SA93-136 incorporated. Models 180, 180A, 180B, 180C, 180D, 180E, 180F, 180G, 180H, 180J, 180K, 182, 182A, 182B, 182C, 182D, 182E, 182F, 182G, 182H, 182J, 182K, 182L, 182M, 182N, 182P, 182Q, 182R, 182S, R182, T182, and TR182. Note: The STA is the Canadian version of the U.S. STC. Requirement: 1. Inspect inside the left and right wings, aft of the spar, closest to where the strut connects to the wing, for an angle stiffener along the lower spar cap between Wing Station (WS) 90 and WS 110, in accordance with Part A of the Accomplishment Instructions of Air Research Technology Inc. (ART) Service Bulletin No. SB-1-96, Issue 1, dated 11 April 1996. 2. If an angle stiffener is not installed, before further flight, install a stainless steel reinforcement strap on the underside of each wing, along the spar at WS 100.50 in accordance with Part B of the Accomplishment Instructions of ART Service Bulletin No. SB-1-96, Issue 1. Note: FAA AD 98-16-04 Amdt 39-10679 refers. Compliance: Unless already accomplished, within 50 hours time in service after 5 November 1998. This Airworthiness Directive becomes effective on 5 November 1998. Background: Test results have revealed that the wings of affected Cessna aircraft, without the angle stiffener, do not meet the applicable design requirements after being modified by above referenced STC or STA. The actions specified by Directive are intended to prevent wing failure during flight caused by the absence of an angle stiffener, which could cause loss of control of the aircraft.