Ignition Override:-
Sorry, but you're almost (but not quite) totally wrong about the Roselawn incident.
Firstly, I'd be grateful if you could detail your authority for your assertion that there were "some serious loss-of-control incidents due to inflight icing happened to ATR-42s in Europe." I am not aware of any.
The aircraft involved in the Roselawn incident was being flown very far indeed from "the prescribed manner".
It was being flown flapless in severe icing with the autopilot engaged.
They were holding for getting on for 45 minutes in those conditions. For at least 25 minutes of that time the Captain was down the back chatting up the cabin crew, leaving a very inexperienced FO up front to handle everything in poor weather conditions. For at least 17 minutes there was one of the cabin crew on the flight deck being chatted up by the Captain.
During those 45 minutes the pitch trim whooler sounded at least five times, indicating to anyone who spared a thought that the automatics were having just a little trouble keeping the aircraft in trim in the conditions.
At no time during those 45 minutes did the crew request higher levels, lower levels, other routings, anything that would take them out of the severe icing they were encountering.
The crew demonstrated some of the worst airmanship possible, a degree of complacency and arrogance that takes the breath away and, sure enough, the earth rose up and smote them.
The FAA/NTSB result on the inquiry was nothing short of a disgrace, exhibiting some of the worst protectionism ever seen between European and American aviation.