AD/A320/88 - Wing Front Spar Vertical Stringers

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/A320/88 Wing Front Spar Vertical Stringers 2/98 Applicability: All A320 models without Modification 21290 or Service Bulletin A320-57-1017 incorporated. Requirement: 1. Perform an eddy current inspection at the top end of the front spar vertical stringers at frame 36 in accordance with the instructions given in Airbus Industrie Service Bulletin A320-57-1016. 2. If cracks are detected, dependent upon SB A320-57-1016 Accomplishment Instructions synoptic chart, repeat the inspection defined in Requirement 1 of this Directive, or contact manufacturer. 3. If no crack is detected, repeat the inspection defined in Requirement 1 of this Directive. Note: DGAC AD 97-311-105 (B) refers. Compliance: 1. Before the accumulation of 24,000 flights. 2. Before next flight or at intervals not to exceed 4,000 flights, as determined by SB A320-57-1017 chart. 3. At intervals not to exceed 14,000 flights. This airworthiness directive becomes effective on 29 January 1998. Background: During full scale fatigue tests, bending cracks were found on the front spar vertical stringer at Frame 36. On in-service aircraft, undetected cracks can propagate and form a long crack in the top end of the front spar vertical stringers.