aircraft has 30.00'' (correctly set) in altimeter. lands at airport 2300' w/o resetting altimeter. on landing altimeter reads 3100'. what is altimeter setting at destination airport.
2007-02-12 15:46:26 · 4 answers · asked by atcwrenzoc 1 in Cars & Transportation ➔ Aircraft
Altimeter settings can be a little bit tricky. But, as a rule of thumb, pressure decreases at a rate of about 1" of mercury per each 1000' increase in altitude.
If you landed at an airport with an elevation of 2300' on the surface, with your altimeter reading 3100', in order to make your altimeter read 2300', you'd have to increase the pressure reading in the Kollsman window since pressure varies inversely with altitude. Thus, since 800' is 80% of 1000', the pressure reading would have to increase 80% of 1" of mercury, or .8 inches. Thus, the altimeter setting should be 30.80. Hope this helps.
2007-02-13 06:58:05 · answer #1 · answered by i love colleen 2 · 1⤊ 0⤋
An altimeter simply reads air pressure. Air pressure will change as a result of altitude change OR the barometric pressure due to meteorological conditions.
If you are on the ground and the actual altitude MSL is known, you should set your altimeter to that altitude. The barometric pressure in the Kollsman widow will now read the actual barometric pressure at that location.
The only time that you actually need to chage the Kollsman window setting is while you are enroute to an airport or landing. With the correct barometric pressure now set in the altimeter it will read your actual altitude accurately at your destination.
2007-02-12 20:56:21 · answer #2 · answered by Gordon B 4 · 0⤊ 0⤋
The easiest thing to do is to wind the altimeter until it shows the airport altitude. (in the absence of a QNH from an ATIS)
The altimeter setting is therefore whatever it takes to read the correct 2300 feet. This is a legitimate and approved procedure....but then Im in Australia and I dont know what your procedures are...
Hope that helps...
2007-02-12 17:30:44 · answer #3 · answered by split_ess 2 · 0⤊ 0⤋
So, it's reading 800' higher than it should?
Why would it read higher?
It thinks it's higher. Why?
The air is thin.
Why would it be thin?
The pressure is low.
How low?
800' worth.
How many inches of mercury does pressure change per 100'?
You figure out the rest.
2007-02-12 16:32:35 · answer #4 · answered by Anonymous · 0⤊ 0⤋