Go check your manual, page 56. Transition to failsafe is NOT instantaneous, it is fixed at 1/4 second. Now granted, 1/4 second may not seem particularly long, but the RX does still get quite a few frames during that 1/4 second, and EVERY ONE OF THEM has to be corrupt in order for the failsafe to kick in - because as soon as a single valid frame is recieved, a new datum is recorded for the point from which another 1/4 sec worth of corrupt frames has to exist before failsafe will be initiated. That is quite a lot different than having the failsafe kick in on just a single corrupted frame, which is what your "instantaneous, no time delay" claim implies.

Even with my old ZPCM systems, I used 1/4 sec anway, and have never once had a failsafe triggered in the 15 years or so that I have been flying PCM.

Gordon

[Edit: typo]