AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/LA -4/26 and issues the following AD under subregulation 39.1 (1) of CAR 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. Consolidated Aeronautics, Colonial and LA-4 Series Aeroplanes AD/LA-4/26 Amdt 1 Wing Upper and Lower Spar Doublers 7/2002 Applicability: Affected aircraft with wing spar part numbers incorporated as specified below: Model Serial Numbers Lake LA-4 246 through 421, 423 through 429, 445, and 446 Lake LA-4A 244 and 245 Lake LA-4P 121 Lake LA-4-200 422, 430 through 444, 446, and all subsequent serial numbers. Lake Model 250 1 through 232 Wing Spar Parts Part Numbers Upper Spar Cap Angles 2-1610-015 and 2-1610-016 Lower Spar Cap Angles 2-1610-075 and 2-1610-076 Upper Spar Doublers 2-1610-061 and 2-1610-081 and 2-1610-065 Lower Spar Doublers 2-1610-063 and 2-1610-083 Requirement: 1. Inspect the left and right wing upper and lower spar doublers for cracks in accordance with the Inspection section of Revo Incorporated Service Bulletin B- 79 R1, Revised 5 January 2000. Consolidated Aeronautics, Colonial and LA-4 Series Aeroplanes AD/LA-4/26 Amdt 1 (continued) Replace any cracked wing spar doubler, before further flight, with a new part that incorporates the same part number (or FAA-approved equivalent part number), in accordance with the applicable maintenance manual. 2A. Incorporate Modification Kit B-79 in accordance with the Kit Installation section of Revo Incorporated Service Bulletin B-79 R1. OR 2B. Incorporate STC ASA052ML. Note: FAA AD 2000-10-22 Amdt 39-11746 refers. Compliance: 1. Within 50 hours time in service after 10 August 2000, or before 10 August 2001, whichever occurs first. 2. Before further flight after Requirement 1 is accomplished. Also, if 2B, inspect regularly in accordance with the STC instructions. This amendment becomes effective on 11 July 2002. The original issue of this Airworthiness Directive became effective on 10 August 2000. Background: The FAA received a report of a fatigue crack found at the second most inboard wing attachment bolt hole on one of the affected aircraft. Similar fatigue cracking has since been reported on seven more of the affected aircraft, including incidents where the fatigue cracking occurred on aircraft with less than 500 hours time in service. Such cracking could result in wing separation from the aircraft with consequent loss of control. Amendment 1 adds an alternative modification. David Alan Villiers Delegate of the Civil Aviation Safety Authority 31 May 2002 The above AD is notified in the Commonwealth of Australia Gazette on 19 June 2002.