A couple a weeks ago I did an IFR dual Cross Country with a student who
had his Garmin 295 (VFR GPS) Mounted in the airplane. I fully believe
in using everthing you got and were were IMC for about 1/2 of the
flight.

Just as we intercepted the Arc for a VOR DME approach in IMC I noted
that the the GPS appeared to be frozen. We flew the full approach to an
actual missed. We never did see the airport and then shot the ILS at
another nearby airport and and were climbing out for our return flight
before we felt like we had enough time to see what was going on with
the GPS. It was completely locked up and still showed us on the Arc for
the VOR DME Approach. We finally had to remove the batteries to reset
it as even the power switch was frozen.

Your DE was just simulating this exact scenario. It was great lesson
for my student.

Brian
CFIIG/ASEL