Originally Posted by rw55
Great pointer to the Airliners.net thread, but it raised another question.
It said that they do it mostly with tail-engined aircraft because of the risk of sucking in Foreign Object Damage (FOD) junk with below-main-wing engines.
Is there extra FOD risk during reverse thrust? Or is it just that pushback or powerback happens close in to the terminal/bridge, where there's more likely to be junk? Underwing-engined jets taxi in that area when they come in. What's the difference?
FOD is Foreign Object Debris, although it could become damage.
As far as I know, the reason is that most FOD is near the terminal, not on the runway. While jets do taxi in that area, the engine setting is much less than it is for reverse thrust. Engines are not really designed to go backwards, which is why you hear WHOOOOOAAAAR during a powerback just to move a couple of MPH (and thus the wasted fuel).