Where does an airliner get power for the lights etc.?

[laserblazer]

Does it take it from the engines or a seperate generator?

[Chris_Jones]

From the engines, theres normally also a seperate Auxiliary Power Unit (often in/near the Tail) that can provide power to start the engines or power the aircraft if an engine fails.

[Hightower]

From the engines, theres normally also a seperate Auxiliary Power Unit (often in/near the Tail) that can provide power to start the engines or power the aircraft if an engine fails.

 

Was watching air crash investigation a while a go, and it said on most commercial air craft a little fan popped out below the plane which produced enough power for vital systems and engine restarts.

 

Clever stuff

[Chris_Jones]

Thats a Ram Air Turbine, basically a wind generator that pops out the side in the event of power failure - The Gimli Glider / Air Canada <- Gimli Glider incident where one was used.

[Butuz]

As Chris said - the APU provides electrical and hydraulic power to the airliner when the main engines are off. The APU is usually a small gas turbine engine (i.e a much smaller version of a jet engine). If you've been boarding an aircraft and wondered why there is heat haze coming out of the tail or why there is a whining sound and the main engines are not moving - that's the APU working. APU is usually field from the main tanks so if you run out of fuel - you run out of APU too!

 

Butuz

[pcstru]

Depends when, where and what type of aircraft.

 

1. A totally dark Aircraft may take power from a ground cart or internal batteries.

2. Larger aircraft generally have an APU - as described by Butuz. The cart or batteries are used to start the APU after which the power bus is switched over and the aircraft takes all power from the APU.

3. Power (and sometimes compressed air ('bleed air') from the APU is used to start-up the main engines. The power bus is then switched to take power from the engine generators and the APU is shut down. For most of the duration of a flight, most aircraft will take power from the main engines.

4. If the engines fail, some aircraft have small wind driven props which can generate power but there are other options including starting up the APU, allowing the engine to spool driven by the air , or running on batteries.

[m25man]

Bah Humbug, forget planes this is how to use 2 x 900cc Gas Turbines...

 

I want one....

 

the C-X75 emits just 29g/km of CO2 and has a range of 560 miles

 

No congestion charge it will save me £10 per day!

Edited January 17, 2011 by m25man

[FN-GM]

From the engines, theres normally also a seperate Auxiliary Power Unit (often in/near the Tail) that can provide power to start the engines or power the aircraft if an engine fails.

 

It wont power the aircraft if the engines fail inflight the fan that Hightower describes does this. Thats a separate unit