"Auxiliary power unit#Spacecraft" . "auxiliary-power unit" . "Auxiliary power supply unit" . . . "emergency power unit" . . "Auxiliary power unit" . . "auxiliary engine" . "airborne auxiliary power plant" . . . . . . . "fossil fuel generators" . . "Airborne Auxiliary Power Plant" . "Aerodynamic control surfaces must be actuated" . "auxiliary gas turbine" . . "auxiliary generator" . "auxiliary motor" . . "APU generator" . "auxiliary power unit" . "APU" . "battery packs" . "Emergency Power Unit" . . "diesel-powered auxiliary drive" . "auxiliaries" . "APUs" . "Auxiliary power unit#Military_aircraft" . . "auxiliary power units" . "Auxiliary Power Unit" . "auxiliary power" . "Auxiliary power unit" .