It would seem a "Low Side" failure would result in either normal Nr or lower Nr than originally set....and a "High Side" failure would result in higher Nr than originally set.
Basically yes. Here is my understanding. A high side failure will cause the engine to increase power up to 120% engine RPM or max torque available. So if you were at 70% torque to maintain 100% Rotor and one engine failed to the high side you would probably see one engine go up to max torque available (TGT limiting), lets say that is 120% torque. Since the total torque before was 140 (70 per engine) the other engine would reduce to maintain 100% by going to 20%.
If you were at 50% torque dual engine torque under the same circumstances than the high side engine would go up to 120% RPM since it wouldn't reach max torque available and the other engine would go to 0 torque.
The question...."If you move the Collective....during a High Side failure....would the Nr not increase if the Collective was reduced and either stay the same if raised slightly?"
I would say from this the dual engine aircraft you operate is the same as a Blackhawk. That is exactly what I would expect to happen presuming the one engine had the power to increase the NR.
A second question....."In a High Side failure....does the N-1, Ng, or whatever it is called in the Blackhawk stay in the governor range or does the engine go to Topping or beyond?"
Below -10C the engine is typically limited by NG, above It's limited by TGT, it is also limited to 120% RPM so if the TGT limiter or NG limiter was not hit it can go to 120% engine RPM in a L model Hawk. The Rotor however is not supposed to go pass 107. Not sure why they didn't limit engine RPM at 107 like they did in a A model.
Next to Last question....."Does the 'Good Engine' respond correctly to Collective Movement?"
I would presume it does as long as one of the limiters is not met.
Final question....."Are you using Torque as the way to diagnose the problem or using Gas Producer and Power Turbine indications along with Nr?" I would suggest the Torque indications are not really that useful in diagnosing the problem. I taught Governor failures by disabling the Torquemeter Indicators or covering them up altogether.
Yes that is how the EP is written. If the RPM R is increased or decreased it's initially a different EP. The procedure is essentially to pull the high TGT engine lever back slowly and see if the other engine torque increases- if it does than it's a high side failure and you continue pulling back to manually control torques close to equal. If the Low engine doesn't increase than it's a low side failure and you can take manual control if the power is needed.
The procedure makes sense to me and I don't really know a better way but if you have a method I'd be interested to hear it. From what you are saying it would seem you could essentially run the same check by moving the collective instead of the Engine Power control levers and I can't see why that wouldn't work.
As the Torquemeter needles do the most moving around compared to other indicators...they seem to attract the eye the most and offer the least useful information.
I have flown seven different Twins and have had every kind of governor or fuel control failure known to Man I think....all but a few were pretty much non-events....while two really...really....really stand out and both of them were in the Chinook. One event that stood out was two different problems....on two engines simultaneously in a very awkward situation and the other was an engine that went to absolute max power and would not respond to any corrective action....in an empty aircraft very low on fuel which made for a vertical rocket with very dangerous Nr speeds
Last edited by Shenanigan; 22nd Aug 2012 at 21:33.