Airworthiness Directives; Aerospatiale Model ATR42-200, -300, -320, and -500 Series Airplanes; and Model ATR72 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Aerospatiale Model ATR42-200, -300, -320, and - 500 series airplanes; and Model ATR72 series airplanes; that requires replacement of the existing uplock boxes of the main and nose landing gears with modified uplock boxes. The actions specified by this AD are intended to prevent a mechanical failure of the uplock box mechanisms, which could result in failure of the associated landing gear to extend. This action is intended to address the identified unsafe condition.