Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 series airplanes. This proposal would require replacing the cam assembly, cam bellcrank assembly, and thrust reverser control switch actuator on all four thrust levers with new components. This proposal is prompted by a report of an uncommanded automatic retraction of the leading edge flaps during takeoff. The actions specified by the proposed AD are intended to prevent such uncommanded automatic retraction, which could seriously degrade liftoff and climb capabilities, and result in near-stall conditions at a critical phase of the flight.