Does the FADEC on the 135 permit any manual control of throttle position or is it simply off, idle and fly?
Imagine for a second that the collective is 'stuck' at a significantly high pitch setting. With engines driving the aircraft can't descend without significant speed increase. How therefore do you establish a controlled descent? In the old days of manual throttles you could reduce Nr to induce a rate of descent but if the choice is either fly or idle its a little trickier.