Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Aerospatiale Model ATR42- 200, -300, -320, and -500 series airplanes; and Model ATR72 series airplanes. This proposal would require replacement of the existing uplock boxes of the main and nose landing gears with modified uplock boxes. This action is necessary 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.