Originally Posted by
wrench1
A separate overspeed system was installed due to the disc failures. You’ll find a number of turbines with hydro-mechanical fuel control systems were designed to use a topping or trim procedure to adjust max engine power like the 101. Plus on this side of the spectrum, most models were transmission limited and you would smoke a transmission or twist a mast before your engine gave it up based on the components I've changed after a "dire" situation or two. But as I recall, most Sikorsky models were engine limited and would expense the engines to keep the blades turning which I always thought was a better priority in the big picture.
Yes, part-power stop and one could sign off the check using that stop as the charts were calibrated for its use as it provided a more stabilized environment vs hanging at the outer limits of the power envelop. There was also a "slave" stop for the PT6s that allowed the check to be done on the ground, however, most used the built in part power stop in flight unless it was super cold outside.
Thanks - been over a quarter of a century!