Definitions for "Auxiliary power unit"
Keywords:  apu, aircraft, kreigs, cab, engine
small engine used to provide power to an aircraft's primary systems (e.g. ventilation and electrical systems) whilst the main engines are shut down.
A small turbine engine used to provide electrical power and bleed air for ground operations only.
a small diesel fuel-powered generator mounted outside the cab that provides the operator heat, air-conditioning, and electrical power to run in cab appliances