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-   -   Too low air pressure to fly (https://www.pprune.org/tech-log/629618-too-low-air-pressure-fly.html)

SpotOn_No 10th Feb 2020 07:26

Too low air pressure to fly
 
Norwegian Carrier Widerøe has had to cancel several flights in the northern part of Norway today due to air pressure being below 946 hPa - which apparently is the certification limit for some of their aircraft (WF fleet consists mainly of DHC-8 variants).

Not a very common occurrence....

Unfortunately I'm not allowed to post URLs or pictures yet, but you can find the story at the website of the Norwegian national broadcaster NRK (.no).

atakacs 10th Feb 2020 19:05

Sounds a bit wierd. That would mean they could not operated any mid to high altitude Airport?!

eckhard 10th Feb 2020 19:32

Perhaps they can’t set anything below 950 on their altimeters?

Dan Dare 10th Feb 2020 19:48

What about QNE?

SimCaptain 10th Feb 2020 20:00

QNH 938
 
Low Pressure Grounds Widerøe's Dash 8 Fleet due to storm "Ciara"...


atakacs 10th Feb 2020 20:13

already here

go-around flap 15 10th Feb 2020 20:37

Reminds me of a particularly long and boring flight a while back where I was finding out what the lowest QNH you can forecast on the 737 FMC by trial and error - not that I can remember the number anymore! Like I said, was very bored.

SpotOn_No 10th Feb 2020 20:50


Originally Posted by eckhard (Post 10684617)
Perhaps they can’t set anything below 950 on their altimeters?

Close. Apparently, the lowest setting possible was 948.

eckhard 10th Feb 2020 21:32


Originally Posted by Dan Dare (Post 10684639)
What about QNE?

Indeed! Bit of a lost art? Modern glass equipment can set very low and high figures on the sub-scale, which makes QNE unnecessary. QNE didn’t figure in the Ops Manuals of my airlines in the last 25 or so years.

Alpine Flyer 14th Feb 2020 19:23


Originally Posted by Dan Dare (Post 10684639)
What about QNE?

You'd need a QNE minimum as well.
FAA AIM recommends not to operate when you can't adjust to low pressure (and once more impressed by how the FAA manages to produce useful information in readable form, an art totally lost to EASA).7.5.2 Low Barometric Pressure

When abnormally low barometric pressure conditions occur (below 28.00), flight operations by aircraft unable to set the actual altimeter setting are not recommended.

NOTE-

The true altitude of the aircraft is lower than the indicated altitude if the pilot is unable to set the actual altimeter setting.







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