It is still unclear what caused Sunday’s crash in Greece, but falling cabin pressure is thought to be one of the factors.
In Swedish airspace there have been 48 incidents of falling cabin pressure in the last five years, according to Swedish Radio’s Ekot programme. The Swedish Civil Aviation Authority will now go through every case to see how that number could be reduced.
The inquiry is expected to be completed in the autumn.
After giving the evidence the once-over, Hans Käll , a flight safety analyst at the Swedish Civil Aviation Authority, observed that four of the Swedish cases involved Boeing 737s – the aircraft which crashed in Greece.
Half of the incidents occurred on the Bombardier Q400 plane and in 30% of cases the pilot was forced to drop quickly. On two occasions the planes’ oxygen masks were triggered.
But Hans Käll said that none of the incidents could be described as dramatic.
“No passengers were in danger or felt ill,” he said.
Käll does not believe that falling cabin pressure alone could have caused the accident.
“There were probably both technical and operational faults,” he said.
At a height of several thousand metres the air pressure is so low that the air does not provide the blood with enough oxygen. An aeroplane’s system maintains the air pressure in the cabin and falling pressure triggers the oxygen masks automatically.
“Altogether on board there should be enough oxygen to last until the plane is down to a safe height for breathing – around three thousand metres,” said Käll