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Argonautical
31st Jan 2012, 14:30
This story is hard to believe for a 4th generation fighter, would a Typhoon be similarly effected?

STOCKHOLM (AP) — High atmospheric pressure is typically associated with good flying weather.
Not so at the Lulea air base in northern Sweden, where about a dozen Gripen fighter jets were barred from taking part in a Nordic air exercise Tuesday because of an abnormally strong high pressure system.
It's not that it's unsafe to fly, says base commander Mats Hakkarainen, but the pressure is so extreme the planes' instruments are being confused by the values and issue error signals.
The national weather agency says the atmospheric pressure in northern Sweden reached a 40-year high on Sunday.
Peter Liander, a spokesman for Gripen maker Saab, stressed that the plane can fly in all kinds of weather, but "the value is so extreme" that flight instruments treat it as an error.

Courtney Mil
31st Jan 2012, 14:52
Synoptic chart show 1052mb. Even the trusty old Mk30 Altimeter subscale could only go up to 1050. So it's not just a gen 4 problem. It may just be a simple as it's out of the design range.

GreenKnight121
1st Feb 2012, 02:36
Much like the Y2K date-error issue for computer systems that were expected (at the time of manufacture) to have all been replaced before it would matter (but they weren't).

The makers of the instruments and/or the programmers of the flight computers simply didn't expect the atmospheric pressure to ever get that high.

212man
1st Feb 2012, 02:52
There was a similar problem about 3 years ago with the Civil Sikorsky S-92 fleet in the North Sea - the QNH was 944 Mb and the ADCs simply ceased to generate outputs! Since fixed....

BOAC
1st Feb 2012, 08:20
were barred from taking part in a Nordic air exercise Tuesday because of an abnormally strong high pressure system. - potential aggressor makes note in diary - 'Check Met charts for pressure'.

Praise the software in these 'modern' jets!

Neptunus Rex
1st Feb 2012, 20:24
Use QNE "the reading on an altimeter with 1013 set." Had to use it once in Entebbe, but that was because the elevation put QFE out of reach.