While testing of FADEC engines under development (with the airframer, engine manufacturer and fuel system developers), we had an interesting experience.
While hovering downwind with 20 knot tailwind, watched the TOT on the right engine start to climb, followed shortly thereafter by one single bang from right engine. I commented that this must have been a compressor stall - flight test engineer from airframer said - yes, but on this helicopter with earlier, non-FADEC engine, it would have been continuous compressor stalls until aircraft exited this situation.
Was later given photos of non-FADEC model with flames coming from both intake and exhaust in downwind hover.
FADEC computer would note condition of compressor stall, and prevent it for duration of flight. Very neat!!!