I have used IPD and when you do get to the end of its range it starts gittering... It does not lock
into some pos or go to some failsafe mode (it can)... All the servos chatter and still follow the trans sticks, just slowly.
It gives you a warning before you loose it..

(I did this on a RC car with a wireless camera... All over the hood while I watched TV.. Good way to test range
on an airplane system)...

Eddie Weeks