I wouldn't be too hard on the AAIB... yes the report was perhaps less complete & conclusive than we would like, but the decisions that led the crew to fly are in my view largely inexplicable. They fingered the *possible* contributing factors - fatigue, effects of drugs - I'm not sure what else the AAIB *could* have done/said.
Definitely worth waving around when issues of fatigue and FTL come up for discussion however!
I was moderately impressed with the tests they did which appeared to confirm the APU running had likely led to asymmetric icing as the proximate cause of the unrecoverable roll - that's a very nasty 'gotcha'. Does anyone know of any other accident where *asymmetric* icing was a factor?
R1