Mr. O,
I learned on the Chinook....one Torque Gauge with two needles, an Nr Gauge, and two N-1 gauges.
We looked at Nr first, followed by N-1's.....the Torque Split merely indicated a potential problem.
As in all helicopters....Nr is of immediate importance.
Is it higher, lower, or as set before the problem....?
Then check the N-1's.....within the Governing Range...or above or below?
That usually told the story for you.
Then perhaps you could decide if it was the AC or DC system that was acting up....as it was an AC system that normally controlled the Nr.....and a quick Circuit Breaker pull would disable that Engine's Governor System and you reverted to direct control of the engine by means of a Momentary switch that you would have to manually balance the faulty engine to the normal one still using the DC system.
Of course there was the possibility of a stuck actuator that showed up as Torque Splits upon moving of the Thrust Lever (For the unwashed heathens....Colllective Lever).
Key to all this discussion is all failures are not Text Book style failures.
GS Pilot and his Instructor Pal are right as well....in that the Good Engine will move according to Collective Movement....but that should be well down the line in the troubleshooting tree and be more a confirmation than a diagnosis method.
At least in my opinion.
Understanding what the "Governing Range" N-1/Ng for your aircraft is will aid in assessing both a high side failure....and particularly a Low side failure....which may determine if it is a Governor Failure or an Engine Failure of some sort that leaves the Engine running but below the Governing Range.
Last edited by SASless; 17th Jul 2017 at 15:57.