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. This action requires an inspection of the crew rest area heat exchangers to detect deflection or interference with the flight control cables; and various follow-on actions. This action also requires replacement of certain nutplate attachment rivets that attach the heat exchangers to the airframe with stronger rivets. This amendment is prompted by a report of interference between insulation blankets adjacent to the heat exchangers and flight control cables. The actions specified in this AD are intended to prevent a reduction in maximum rudder and elevator surface deflection due to the separation of heat exchangers from the body frame, which could result in reduced controllability of the airplane.