Originally Posted by
switch_on_lofty
AAIB second special report published
Sala's blood contained Carbon Monoxide at over 50%, which is considered a potentially fatal dose.
That changes things somewhat - 50% is well over the fatal concentration. Carbon monoxide is a byproduct of incomplete combustion, so that is most likely to be either exhaust leakage into the cabin or a fire. This might throw a new light on the strange behaviour of the plane in the last few minutes of flight if the pilot was also being overcome by fumes.