Failures in Pro Pilot

[EHM-1570 Bruce]

I assume that one of the possible failures that a pilot may encounter is a radio failure. On one of my previous flights I decided to simulate a radio failure while under the control of MSFS ATC, I squawked 7600 to see what would happen, the response from ATC was that my Transponder was malfunctioning and to squawk my original squawk code. This will be a disaster if it happens, because ATC will not give priority to the aircraft with no radios, and will allow aircraft to enter the runway when you are landing, also will not give go arounds.

[EHM-0502 Desmond]

As a sort of follow-up, is there a way to see if you had a failure in Propilot, so you can see if yoy actually noticed?  I mean, if the GPS fails, and you are not using it, you would not notice it had failed.
Also, how frequent are the failures?