Quote Originally Posted by Wales-Bales View Post
Not all light aircraft have de-icing systems fitted, which may suggest that they are optional. One of the ways to defeat icing conditions is to climb to a higher altitude of around 25,000ft into commercial airspace, but the pilot didn't have the correct rating to take that course of action, hence he requested a decent to a lower altitude. However, the cause and timing of the carbon monoxide exposure is still unknown (to us), so all possible avoidance strategies may have been futile. It sounds like a case of whatever could go wrong, did go wrong on this flight.
This aircraft did have de-icing equipment fitted according to the engineer who said it wasn't fit to fly (other than short distance for repairs). At that time the de-icing wasn't functioning. The aircraft then went to a second engineer who carried out repairs. Let's hope he did a good job to repair the malfunction. If not, the aircraft may have got through its annual inspection only to fly without de-icer functioning correctly. From memory, it has been reported that the aircraft log book went down with the plane. What happened regarding repairs and subsequent flights would certainly be of interest to AAIB.