Airworthiness Directives; Schweizer Aircraft Corporation Model 269A, 269A-1, 269B, 269C, 269C-1, and 269D Helicopters

This amendment adopts a new airworthiness directive (AD) applicable to Schweizer Aircraft Corporation (SAC) Model 269A, 269A-1, 269B, 269C, 269C-1, and 269D helicopters. This action requires inspecting the tail rotor swashplate shaft (shaft) nut for looseness and, if loose, inspecting the shaft for proper size; subsequently inspecting the shafts not previously inspected; and replacing any undersized shaft prior to further flight. This amendment is prompted by the discovery of an undersized replacement shaft during routine maintenance. The actions specified in this AD are intended to prevent failure of the shaft and subsequent loss of control of the helicopter.