What is altimeter used for?
altimeter, instrument that measures the altitude of the land surface or any object such as an airplane.
What is altimeter and barometer?
Both the devices – an altimeter and a barometer – are used to measure pressure. Some altimeters are barometric, which means they measure altitude by calculating air pressure of a specific location. Barometers determine the changes in elevation as well as the changes to the air pressure caused by weather patterns.

What are the types of altimeter?
The main types of conventional altimeter which have been used in aircraft are:
- Three-pointer altimeter;
- Drum-pointer altimeter;
- Counter-pointer altimeter; and,
- Counter drum-pointer altimeter.
What is an altimeter on a plane?
An ordinary aircraft altimeter is nothing more than a sensitive barometer, an instrument that measures air pressure. It works to measure height above sea level because the air’s pressure decreases at a more or less regular rate as you ascend. Standard atmosphere tables show how this works.
What are the units of an altimeter?

The most common unit for altimeter calibration worldwide is hectopascals (hPa), except for North America and Japan where inches of mercury (inHg) are used. To obtain an accurate altitude reading in either feet or meters, the local barometric pressure must be calibrated correctly.
How do you read an altimeter?
Read the numbers on the drum, then look at the pointer and add the 100s and 20s to the numbers on the drum to get your altitude. For example, if the drum reads 6000, and the pointer is at the 2nd line past the 2, then you would read it as 6000+200+40=6240. Your altitude is 6240 feet.
Who invented the altimeter?
Paul Kollsman
In 1928, Paul Kollsman forever changed the way pilots would fly. By introducing the first accurate barometric altimeter, an instrument used to measure the altitude by calculating barometric pressure, “flying on the gauges” became possible.
What altitude does altimeter read?
Radio or radar altimeters measure absolute altitude, usually up to 2,500 feet AGL. This type of altitude is crucial during approach and landing as it gives pilots an indication of how far the aircraft is from the ground.