What happened
On 21 January 2019, a Piper PA-46-310P Malibu, registered N264DB, went down in the English Channel. The aircraft was flying approximately 22 nm north-north-west of Guernsey when it disappeared from radar. The wreckage was later discovered on the seabed at a depth of 68 metres, positioned near the final secondary radar point recorded by Guernsey air traffic control.
The accident resulted in one fatality and one person remains missing. The recovered remains were identified as the passenger. The aircraft was destroyed upon impact with the sea.
The investigation
Investigators focused on medical evidence found during the recovery process. Toxicology analysis performed on the blood of the passenger revealed a carboxyhaemoglobin (COHb) saturation level of 58%. This level of carbon monoxide saturation is generally considered potentially fatal for a healthy individual.
Because the cockpit and cabin of this aircraft type are not physically separated, the AAIB established that the pilot was likely subjected to similar levels of exposure. The investigation is currently working alongside the NTSB and aircraft and engine manufacturers to determine how carbon monoxide may have entered the cabin, specifically looking for leaks in the heating, ventilation, or exhaust systems.