I posted this earlier...sorry if this wasn't understood. For clarity I posted:
So on the 135, are you saying that an engine can fail to the extent that it becomes a net torque drag, without a command input, without a clear cockpit alarm? Strikes me as a bit of an oversight.
JT2, Helilog -- No, I meant torque. G-SPAO had 2 Turbomeca Arrius 2B2 turboshaft engines each with a shaft out to the rotor. If one engine underproduces or fails then instead of providing a useful power, it becomes a drag on the working engine. A torsional strain gauge would show a reversal of torque on the dead, idling shaft. Instant output with very high reliability, proven third generation technology. I cannot see any reference to such an alarm in the flight manual either as an instrument or as part of a procedure -- indeed, the procedure suggests that there is no such alarm. Instead, it depends on the pilot sensing small corrections. Seems unnecessary and potentially dangerous when the workload is high.