What does an Auxiliary Power Unit do?

The auxiliary power unit (APU) is a small gas turbine engine mounted in the tail cone of an aircraft to provide autonomous electrical and mechanical power for the following: Starting power for the main engines. Pneumatic power for cabin air conditioning systems. Shaft power for other pneumatic and hydraulic systems.

Where is the Auxiliary Power Unit?

tail cone
The APU is a small jet engine which is normally located in the tail cone of the aircraft but, in some cases, is located in an engine nacelle or in the wheel well.

Is Auxiliary Power Unit a generator?

An APU isn’t just a generator, though. It’s actually a miniature engine. Typically found on the tail or around the wheel well, it provides power to the airplane’s electrical devices and systems as needed.

What is APU and GPU in aviation?

The APU (Auxiliary Power Unit) is the power unit contained on an aircraft which can provide electrical and pneumatic (air) power. The GPU (Ground Power Unit) is connected by the ground crew when the aircraft arrives at the gate an provides electrical power only.

Does APU use fuel?

First, the APU runs on fuel and generally represents about 2-2.5% according to IATA. Air Conditioning Unit (ACU) and Ground Power Unit (GPU) can also be used to provide energy on the ground but should not be deployed in addition to the APU.

How is an APU started?

APUs are like small jet engines, small enough to be started electrically. So you would use the power of the battery or an electric ground power cart to spin up the APU by its electric starter motor, and then introduce fuel into it once its spinning fast enough, just like a jet engine is started.

Can plane fly without APU?

Without an APU an aircraft would depend on GSE only for starting one engine with pressurized ground supplied air. Aircraft are allowed in general to fly without an APU. Exceptions are flights with two-engined aircraft and long routes over water or terrain without an alternate airport – so called ETOPS flights.

Which is better APU or GPU?

Even though APU acts as both CPU and GPU, the combination of CPU and dedicated GPU will outperform an APU or a CPU with integrated graphics card.

How much fuel does an APU use in an hour?

between 0.1 and 0.5 gallons
They generally burn between 0.1 and 0.5 gallons of fuel per hour depending on their design, the ambient temperature, the sleeper’s insulation, and the resulting HVAC load, along with the AC power being generated.

Can we start engine without APU?

Yes. Most aircraft switch off their APUs in flight. Also, APU is not mandatory for ground operations if external (Ground) power unit is available. Engine start can be done with an external unit or (in some cases) battery.

How much power does an APU produce?

Aircraft APUs generally produce 115 V AC voltage at 400 Hz (rather than 50/60 Hz in mains supply), to run the electrical systems of the aircraft; others can produce 28 V DC voltage. APUs can provide power through single or three-phase systems.