Auxiliary Power Unit Apu Compartment

A typical apu compartment.

Auxiliary power unit apu compartment.

Auxiliary power unit rev 41 jul 08 2004 flight crew operating manual. An auxiliary power unit apu is a device on a vehicle that provides energy for functions other than propulsion they are commonly found on large aircraft and naval ships as well as some large land vehicles. Automatic shutoff of air source. It is isolated from the rest of the airplane by a firewall.

Aircraft apus generally produce 115 v alternating current ac at 400 hz rather than 50 60 hz in mains supply to run the electrical systems of the aircraft. Operation and control of the apu electric and bleed system is performed at the electrical and bleed air conditioning anti ice panel respectively. The purpose of the ejector is to ensure t hat a steady fl ow of air. Apu compartment while the sep arate consists of two inlets one for the apu engine and the o ther for the apu compartment.

If the apu egt reaches 620 650 c the bleed air valve will modulate toward. However if you should accidentally take off with the apu on the busses then it will continue to power both busses. The unit provides compressed air for air conditioning while the airplane is on the ground and at limited altitude in flight. The auxiliary power unit apu is a honeywell gas turbine hgt400 g.

Automatic shutdown of the apu. The airborne auxiliary power is obtained from a gas turbine auxiliary power unit apu. Standardized definitions of safety significant propulsion system and auxiliary power unit apu malfunctions and rationale for definition changes from the first report. The galley power will automatically be load shed if the apu load reaches 165a.

Standardized definitions of propulsion system and apu related aircraft hazard levels based on the consequences to the aircraft passengers and crew and rationale for. Others can produce 28 v. For apu operating limitations refer to the flight crew operating manual fcom csp 700 6 vol 1 chapter 2 limitations. The auxiliary power unit apu is installed within a fireproof titanium enclosure in the aft equipment compartment.

The apu compartment is by definition a fire zone see fig. An improved passive cooling system for an aircraft apu compartment that includes a lightweight annular air cooled oil cooler that is strategically oriented and shrouded to face its annular inlet away axially downstream from the exhaust of the apu to make it inherently fireproof to flames from the apu or any location within the apu compartment that fuel can accumulate. The generator is rated at 30 kva and produces 115 vac electrical power for backup to the main engine generators refer to chapter 7. It also provides pneumatic power for the environmental control system ecs and for main engine starting on the ground and in flight up to 30 000 feet.

The apu is a fully automated gas turbine power plant which drives an electrical generator. The apu is a compact self contained unit that provides compressed air for engine starting on the ground.