PTH
Any chance of further info on those reports - it is not something I've heard. Having said that, I've not seen anything to the contrary either! If you have a link to the Bombardier stuff I'd be most grateful. They must be slightly worried about this happening in the Q400 as our manual says that, in severe icing, we should disconnect the AP - I've taken this to mean "watch out for tail-plane icing and the controls (in pitch) going a bit wonky" - however, I don't think there is any guidance about what to do if said controls do "go wonky", let alone if there there is a pitch down/tail stall nor what to do if the stall warner/pusher then kicks in!
I agree that it is important to find out if there is any such advice (or not) and if there is, did the Colgan pilots have the up-to-date info. As I say, any official advice would be greatfully rec'd.
Flipster