What instrument measures the altitude of an airplane?

Answer 1

Aircraft use an altimeter to measure the current altitude. The altimeter uses barometric pressure to sense the altitude. As you go up in altitude the air gets thinner. The higher you go the thinner it is. The altimeter is basically just a very sensitive barometer (a barometer is a device used to measure air pressure), so sensitive in fact that it can reliably detect differences in altitude as small as 10 feet.

The drawback with using this method is that barometric pressure varies greatly depending on the local weather. Thunderstorms, for example, always bring with them a sharp increase in barometric pressure, and so pilots must always ensure that their altimeter is set to compensate for these differences.

Another drawback with this method is that it only measures altitude above sea level. When you take into consideration that as you get away from the coast, the ground may well be thousands of feet above sea level, you can see why this may pose problems. As a result all aviation charts have the altitudes of all airports, and most other objects posted on them.

To combat these problems, many more sophisticated aircraft use radar or laser systems to determine their altitude above ground. Additionally, GPS can be used to determine altitude, which is getting more and more common. Neither of these solutions seek to replace the altimeter, but flight crews do use them in concert to maintain accurate information on their position. Also, (for altitudes generally below 2500') radar altimeters are used to measure actual height above the ground.

Answer 2

A ruler or tape measure is used to find the height of an airplane, usually

while it's on the ground.

When it's flying, an altimeter is used to find its altitude ... its distance

either above ground or above sea level.

Answer 3

Depending on the size of the plane and where it's going, the height can be anywhere from about 1500 feet to over 41000 feet.

Answer 4

Tie a peice of string to it and when it reaches its peak grab it and measure!