Question about reverse thrust usage

[Guest]

In real world operations I seem to interpret that reverse thrust is normally cancelled when the aircraft decelerates through about 70kts on rollout. I also remember reading this is because of FOD potential at and below this airspeed. Is this correct?If so, why are the engines more susceptible to FOD under these conditions? Thanks!

[Guest TerryT]

I would guess the way the reversers blow the air around the engine. What ever is loose on the ground could be blown into the intake more easly than when the engine is running normally.Terry

[Guest Iz]

You can imagine that when you're standing still and you're selecting reverse, you're blowing up all sorts of stuff in front of the engine which could then be sucked into the engine inlet.When you're still doing 100 knots, you're going too fast for stuff to actually be kicked out in front of the engine, but there comes a time when you slow down and the stuff catches up with you, so to speak :)Technically, you can use reverse all the way to a stop if you so desire but it's wise to cancel reverse by 60 knots to avoid FOD.Iz

[Guest]

Iz,Good analogy, I understand the situation now, thanks. Man, I gotta tell ya, I am extremely excited about your 757/PIC FDE to be included with the upcoming iFDG V2 757 release!!!!!!!!!!! I can't wait to try it out, it's fantastic that practically everything will seamlessly integrate with the PIC panel.This has to be the add-on of the year for heavy iron fans!