The plane was transporting mail from Norwegian airport Gardermoen to Tromsø when it sent out a distress signal and crashed in Swedish airspace at around midnight between January 7th and 8th, killing its Spanish captain and French co-pilot.
On Monday the Swedish Accident Investigation Authority published its final crash report, putting the majority of the blame on two instruments of the Canadair CRJ 200 aircraft sending out contradictory alerts.
“One pilot suddenly received information that the aircraft was rearing sharply upward when it was in fact flying straight ahead. Because it was dark outside, the pilots had no points of reference,” the authority's chairman Jonas Bäckstrand told Swedish news agency TT.
Another signal was meant to warn that the two indicators were contradicting each other, but only flashed for a few seconds and was likely missed by the pilots.
“The system is constructed like that in some models, to sort out superfluous information, which we criticize in our report,” said Bäckstrand.
The pilots then tried to correct what they believed was the aircraft rearing by steering its nose downwards, which instead caused it to dive almost vertically towards the ground.
“The crew was active during the entire event. The dialogue between the pilots consisted mainly of different perceptions regarding turn directions. They also expressed the need to climb. At this stage, the pilots were probably subjected to spatial disorientation. The aircraft collided with the ground one minute and twenty seconds after the initial height loss,” read the report.
“The two pilots were fatally injured and the aeroplane was destroyed.”
The report also criticizes Swedish search and rescue efforts. The first helicopter, which was stationed in Umeå, did not take off until an hour and 19 minutes after the alarm was raised. It was not equipped for mountain rescue and first had to pack appropriate gear, stated the report.
“That is not acceptable. This was at a time when it was not known if there were any survivors or not,” said Bäckstrand.
The Swedish Maritime Administration (SMA), which is responsible for sea and air rescue operations in Sweden, said it was surprised at the criticism, but admitted more training was needed.
“Looking at the resources involved, you can see that the starting times were pretty long for all units. Flying in mountainous terrain is complex,” SMA's Mattias Hyllert told TT.