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 removal and reconfiguration of the battery grounds of the auxiliary power unit (APU). This amendment is prompted by reports of smoke or fire coming from the APU due to battery grounds that were not installed or maintained properly. The actions specified by this AD are intended to prevent overheating and heat damage of the APU battery grounds due to improper installation of the APU battery ground, which could result in heat damage and consequent smoke or fire on the airplane.