Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Aerospatiale Model ATR72 series airplanes. This proposal would require modification of the pitch uncoupling mechanism of both elevators. This proposal is prompted by reports of fatigue cracking of the pitch uncoupling mechanism and the torque tube of the elevator. Failure of the pitch uncoupling mechanism due to fatigue cracking could result in the uncommanded uncoupling of the elevators. The actions specified by the proposed AD are intended to prevent such fatigue cracking and subsequent uncommanded uncoupling of the elevators, which could result in reduced controllability of the airplane.