What would be the rough variation in indicated altitude on an instrument of an aircraft, sitting on the ground at sea level,
if the air pressure went from low to high or vice versa.
Talking in terms of the maximum and minimum you are likely to get in the UK.
Or in other words, what could be the ( approximate) maximum an unadjusted instrument could be out by (in feet) ?
I only ask out of interest.
By: AlanR - 11th December 2012 at 22:20
Thanks for the info
By: BlueRobin - 11th December 2012 at 19:07
50 feet for every 2mb up to 37000 feet assuming standard atmosphere model
By: Matt-100 - 11th December 2012 at 18:45
The highest recorded pressure in the UK was 1055 mb (1902), the lowest was 926.5 mb (1884).
Let’s assume you adjust the altimeter to 0 feet at the high pressure of 1055 mb. As the pressure decreases, the sensors believe your ascending – once you reach 926.5 mb the altimeter will be showing 3576 feet.
Of course, these are two extremes – I expect even the most severe of cold fronts wouldn’t adjust the altimeter by any more than ~400 ft?
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December 11, 2012 at 2:42 pm