how to calibrate altimeter?

Answer 1

Just set it to field altitude when on ground. Then compare bar pressure reading on alttimeter to current pressure from weather station. If they are the same you areOK

Answer 2

For altimeter calibrations, you must first determine the ambient absolute air pressure. There are several ways to do this. The easiest is if you have access to mercury barometer or a digital pressure gauge. If using a mercury barometer, convert the inches of mercury to lbs/ft2by multiplying inches of mercury by (2116.22/29.92), or 70.729. Don't try this with an aneroid barometer (a weather barometer), since these barometers are usually adjusted to read a pressure adjusted to sea level. If using a digital pressure gauge, just read the pressure directly.

If you don't have access to this fancy equipment, there are other methods. If you have an accurate aneroid barometer, you can read the sea level adjusted pressure on it. Alternatively, find out the barometric pressure (altimeter setting) from a nearby control tower, or get the barometric pressure off of the Weather Channel. As long as there is no frontal weather activity in the area and the reading is taken reasonably close to where you are, it should be close enough. Don't get the altimeter setting by setting your altimeter to the field elevation. This would be meaningless since you are trying to calibrate this instrument!
The airspeed indicator and altimeter are both pressure gauges. The airspeed indicator is a differential pressure gauge, and the altimeter is an absolute pressure gauge. Therefore, if we can apply a known pressure to the gauge, we should be able to calculate what the instrument should have indicated. Then we compare what the instrument should have indicated with what it did indicate to determine the instrument correction.

So when I say a "known pressure," do you have visions of a complicated, expensive laboratory instrument costing thousands of dollars and requiring a major chapter fund-raising drive to purchase? If so, you need to learn to think simple. All you need is a clear plastic tube and some water, and you can create a manometer, a precision pressure measuring instrument requiring no calibration. Manometers have a great history, being used for many years to measure pressure in wind tunnel experiments (and still used in some application). This method is based on the idea that manometers can not only be used to measure pressure differences, but to create them as well.

http://www.eaa1000.av.org/technicl/instcal/instcal.htm

Answer 3

Contact the Local NOAA station, give them your GPS Loc #, and they will give you the data.
Or the air traffic control tower can tell you exactly what alt you are currently at.
This in no way is an Actuall Calibration, but this is a temporary Set Mark for your Current Altitutude. Widgets and gidgets can be off while in actuall flight, so that Mountain that reads 12,567' you may have to be at 12,967' to clear it. This is the basics of Calibration. Your unit must read true and be in compliance with the data provided.

Answer 4

Hi. Prior to take off, rotate the adjustment knob to set the reading to the airport's altitude. Getting a bit obsolete with the 3D GPS system now available. If the altimeter is for sky diving, set the same way as for a plane prior to the jump flight.

Answer 5

Huh.