On 22 Dec 2004 22:26:08 -0800, "Ramapriya" wrote:

I know that a car's engine needs to be mated to the transmission for
propulsion. This I know isn't the case with an aircraft with a jet
engine; if the engine is turned on without the brakes applied, the jet
of air leaving the engine will hurl the craft forward.

My doubt is, why does this forward motion effect not occur during
push-back, when the engines are normally turned on? Is it because at
low revs the engine would lack the punch to initiate the forward motion
of a heavy aircraft? If not, I'd imagine the push-back becomes a bit of
a tiresome affair by the time it's over...

Sorry if this is infuriatingly elementary, but I need to ask somewhere

As others have mentioned, there is not so much thrust generated by the
jet engines at idle that the tugs cannot overcome it to push it back.
Take a look at the tugs sometime, they are massively constructed with
extra weight added on so that they have sufficient mass to push and
pull the big jets.

In addition, next time you are take a flight in a jet airliner, notice
how much power the pilot has to make the engines produce in order to
get the airliner rolling.

Corky Scott