AD 97-11-12 62 FR 28997

This amendment adopts a new airworthiness directive (AD) that applies to Aerospace Technologies of Australia Pty Ltd. (ASTA) Models N22B, N22S, and N24A airplanes. This action requires repetitively inspecting the stub wing upper front spar cap flanges for cracks, and repairing any cracked part. This AD results from fatigue tests that show that the stub wing upper front spar cap flanges could fail over time because of fatigue. The actions specified by this AD are intended to prevent structural failure of the front spar caused by cracks in the stub wing upper front spar cap flanges, which could result in loss of control of the airplane.