Devil, as I have never flown an EC-135:
does it have an oil pressure guage on the instrument cluster?
Good point on needing oil for the oil temp to register.
Non-PCPlod: I lost a shipmate some years ago in daylight to loss of T/R thrust.** The point your raise is worth considering, though I suspect that if the connection between TRDS and the Main Transmission were broken, such that no rotation was provided to the fenestron due to the drive link being broken all at once, the AAIB would have already put out the alert message. I think that such a breach of drive train integrity would be apparent to the investigative team by now. (If I am wrong, apologies to all on the team). This leaves open the question of "why rotors not damaged, hence not turning" per the evidence available to date.
TC's series of analytical posts account for the bulk of the evidence available to date, and paint a chilling portrait of the last few seconds in that aircraft.
RIP, gents.
** The crash where my shipmate died happened at A/S of about 100 kts, at between 300 and 500 ft AGL/MSL (same, as he was flying over a waterway out of a port on the coast) and was a surprise event.
The surviving pilot related how quickly they lost directional control ... the initial yaw due to T/R loss was not obvious at first, initially countered by pedal input due to yaw, but "yaw, full pedal, hey, it's -- " as the helicopter got broadside to the airstream, the A/S fell of rather quickly and what was wrong became apparent to them all of a sudden.
They lowered collective, down they went, flare, chopped throttles (might have flared a bit high, might have pulled the engines early, hard to say, no FDR) hit the water hard and more or less flat. The seats stroked full down.
He got out. (Back was a mess for a few years)
The fella in the back got out.
The guy not flying was knocked out by his head hitting the cyclic. (That was figured out later). He drowned.