Airworthiness Directives; Boeing Model 747-400 Series Airplanes

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