Jellycopter - I just think it is down to training - and that includes knowing the cards through self-study and practice in the simulator.
I think the difference between a TR drive failure and a TR control failure is quite clear, perhaps because I have taught it quite a lot.
TR drive and TR control failures were mandatory parts of the 6-monthly sim on the Sea King as I am sure they are on many other types.
I don't know what you would call the two conditions that would be any clearer.