COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Airbus Industrie A319, A320 and A321 Series Aeroplanes AD/A320/81 Connecting Angle Between Frame 56 and Frame Support at Stringer 38 5/97 Applicability: A320, all models and serial numbers without Airbus Industrie Mod 20941 embodied, or Airbus Industrie SB A320-53-1011 incorporated. Requirement: Inspect in accordance with A320-53-1084 Rev 1. Note: DGAC AD 96-237-090(B) refers. Compliance Before the accumulation of 20 000 flights; thereafter at intervals not exceeding 12 000 flights; unless cracking has been detected, in which case, in accordance with thresholds and intervals specified in the Requirement Document. This Airworthiness Directive becomes effective on 24 April 1997. Background: This Directive is raised in order to detect cracking in the subject connecting angle, which could affect the structural integrity of the aircraft.