Airworthiness Directives; Schweizer Aircraft Corporation and Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, 269D, and TH- 55A Helicopters

This amendment adopts a new airworthiness directive (AD), applicable to Schweizer Aircraft Corporation and Hughes Helicopters, Inc. Model 269A, 269A-1, 269B, 269C, 269D, and TH-55A helicopters, that requires a visual inspection of the bond line between the main rotor blade abrasion strip (abrasion strip) and the blade for voids, separation, or lifting of the abrasion strip; a visual inspection of the adhesive bead around the perimeter of the abrasion strip for erosion, cracks, or blisters; a tap (ring) test of the abrasion strip for evidence of debonding or hidden corrosion voids; and removal of any blade with an unairworthy abrasion strip and replacement with an airworthy blade. This amendment is prompted by four reports that indicate that debonding and corrosion have occurred on certain blades where the abrasion strip attaches to the blade skin. The actions specified by this AD are intended to prevent loss of the abrasion strip from the blade and subsequent loss of control of the helicopter.