Originally Posted by
RAT 5
There were a/c with too small rudders, (VMCA) when with an engine failure, and the other at full power, is was necessary to reduce thrust to gain control. Not the first instinct unless trained.
This is golden info, thank you very much.
Someone asked me "Risk of what?" when I queried as to whether reducing thrust is safe to do without a definite indicator of thrust reverser deployment. The risk I imagine is making your energy state worse on takeoff or climb by reducing throttle on one or both engines before you know exactly what the problem is.
In a few incidents I can think of, the crew instinctively shut down either the wrong engine, or shut down an engine still providing forward thrust, just a little after takeoff.
There was a Taiwanese Dash 8 Q400 that crashed because of this. The aircraft had been experiencing engine trouble on previous flights and assumed that it was the same engine causing the problem this time. The pilot shut it down without confirming that it was indeed that engine experiencing the problem. In actuality it was the other engine which was not performing correctly this time and he shut down the only engine still operating normally.
Another incident I can think of is the Concorde crash, where the flight engineer shut down an engine (or both? Can't remember) because of the fire warnings going off. That engine was still providing thrust and if he had not done that, they may have had a chance of getting more speed and altitude. Of course they were in trouble due to the severity of the fire burning through the wings, but if the engine had not been shut down they may have had more time to deal with the problems, possibly saving the aircraft.
Those types of incidents make me very wary of cutting throttle in takeoff or climb before knowing what is causing the problem for certain.
Is it safe to assume that if the reversers do deploy for whatever reason, we can expect reliable indicators and should just reduce thrust? Again, would unloading the wings save you from uncontrollable roll at lower airspeeds like 190-230 knots? Perhaps lower wing loading would give you enough rudder/roll authority to at least look for other possible causes.