COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Morovan Zlin Z 526 Series Aeroplanes AD/Z 526/2 Main Wing Spar Corrosion 11/96 Applicability: All models Z 526 aircraft. Requirement: Inspect in accordance with Morovan Mandatory Service Bulletin Z 526/69a. Note: Czech CAI AD 2-016/96 refers. Compliance: Before 10 November 1996, and thereafter at intervals not to exceed 12 months. Background: The Czech civil aviation authority received reports of exfoliation corrosion on the main wing spar flanges which seriously degraded the structural strength of the wing.