Calling all DU pilots!

I need to know how much fuel jet engines burn on idle.

One thing I have noticed about United Airlines is that usually they leave the engines running during lengthy taxiway holds, after arrival at the gate, and generally during times where engines could be shut off to save fuel. I am trying to get an idea of exactly how much fuel is wasted here so I can suggest that UAL institute policies promoting fuel conservation.

Of course, as I would be writing to a corporation always looking for ways to cut costs, I would need to put this in economic terms--that is, how much money they could save in fuel costs. For this, I also need to know the price of jet fuel.

I need single-engine idle fuel burn rates for:

Boeing 737, 747, 757, 767, 777

Airbus A319/320/321

Regional jets (although these flights are operated with outside contractors)

Also, if anyone could give me an approximation of what percentage of UAL flight segments are flown by each aircraft type, that would be extremely helpful.

I probably should post this in the environmental forum, but I'm afraid it will go unnoticed there.

Thanks for any help you could provide!

I bet he could answer

at RollsRoyce, Pratt and Whitney, etc.

I did a quick search on www.geae.com (General Electric Aircraft Engines) but could not quickly find fuel burn rates.
i am sure it is there somewhere. You might check the websites of Boeing and Airbus

www.Boeing.com

www.Airbus.com

Also, GE's major large engine competitors are:

www.Pratt-Whitney.com

www.Rolls-Royce.com

Although i am not a pilot, i have flown hundreds of times on commercial airlines and i can't recall there ever being an instance when shutting down the engines after pushback would have been practical, regardless of the length of delay.


Hope that helps a little

Edit: My mother works for UAL and she told me that there are lots of times when it is practical to shut down one engine (but not the other) for delays. However, UAL rarely does this. She also told me that Southwest is really good with this as they will economize any way they can.

If you are not a pilot, it might be difficult to recognize when one engine is shut down while the other(s) are still making background noise that you're not paying attention to anyway.

Turbine engines are cranked by blowing compressed air against one of the rotor wheels. On a jetliner, you start the first one off the little cart that's always connected to the plane on the ramp, then light off the rest of the engines from the one that's running. (Small jet aircraft have onboard compressors.)

Also consider: part of the maintenance intervals for big turbines predicate on the number of starts--and maintenance on a big turbine is expensive.

Given that maintenance is more expensive than fuel, they'll leave the engines running.