Norwegian regional airline Widerøe has had some of its fleet grounded for a rather bizarre reason. A period of extremely low pressure across the north of Norway has meant it cannot fly its Dash 8 turboprops. As a result, around 70 flights have been canceled today.
Widerøe’s stormy grounding
We’ve seen some bizarre effects on aviation from the onset of storm Ciara. From airlines grounding flights and being diverted to far off airports to aircraft making it across the Atlantic in record time, the consequences of this storm have been unusual and far-reaching.
However, today we found out about another strange aviation effect from this stormy weather: the grounding of Widerøe’s Dash 8s. Forbes reports that Widerøe’s fleet of Dash 8 turboprop aircraft are unable to fly due to an extremely low-pressure area across northern Norway.
As a result, more than 70 flights were canceled today, which included pretty much every flight to and from Tromso, Bodo and some of the smaller airports served by Widerøe.
What’s the problem with the weather?
The extreme low pressure over northern Norway doesn’t actually stop the planes from flying. That would be silly. No, the problem here is that it interferes with the aircraft’s instruments, making it very difficult for the altimeter to accurately calculate the distance between the plane and the ground.
Of course, pilots conduct rigorous altimeter setting procedures before flying, to account for barometric pressure changes. Ensuring these are correct is essential to the aircraft maintain separation both from the ground and from other aircraft around them.
The Dash 8 has adjustable altimeters, just like any other aircraft. However, this particular plane has a lower limitation of 948 hectopascals (hPa). In some areas of Norway, the ambient pressure dropped some measure below that level, making it impossible to set up the altimeters accurately. The consequence of this could be highly dangerous, as pilots would not know their altitude in the event of bad weather or poor visibility.
A record-breaking low
This sort of problem doesn’t happen every day. Norway’s meteorologists have said that 22 of their weather stations have seen low-pressure records broken today, the lowest seen in the 30 years of monitoring.
While there are things pilots can do to compensate for lower pressure than their instruments can be calibrated for, it’s not an ideal situation. A Widerøe spokesperson told Forbes that canceling flights was the best option to ensure safety on the airline.
Widerøe is an extremely Dash 8 heavy airline. It flies 23 of the smallest Dash 8-100s, three -200s, seven -300s and 10 -400s, for a total of 43 aircraft. The only flights completely unaffected today were those longer ones using the airline’s three Embraer E190-E2 jets.
Despite Norway’s record-breaking low-pressure today, the lowest ever pressure reading in the nation still stands. The lowest reading was pegged at 938.5 hPa in 1907.
Were you affected by Widerøe’s cancellations? Let us know in the comments.