The plane times the beam and calculates its altitude in kilometers by multiplying the time in seconds by 150,000 that's 300,000 divided by two: Not everyone wants to wear an altimeter all the time, however, and altimeter watches with digital LCD displays, such as those made by Suunto, are more popular with hikers and mountain climbers.
How does a radio altimeter work?
In truth, this altitude is really a pressure, that only converts into an altitude by assuming a standard pressure above a simulated reference plain.
At least, that's where we reset the altimeters earlier today... Here, it is 29. How a pressure altimeter works: Additionally, GPS can indicate true altitude, and terrain-following radar can produce very accurate AGL measurements below transition.
Sign up using Facebook. Once an aircraft descends below the transition level , they receive local weather information which includes air pressure. Konrad Ebeling Konrad Ebeling 49 2. Some of Earth's mountain ranges are surprisingly high and harder to miss in bad weather than you might suppose. Retrieved from https: Photo by Lance Cpl. The very first one made its debut on September 24, 1929 in a pioneering "instrument flight" by Lieutenant General James H.
Hg on the altimeter subscale. Hey presto, tiny changes in air pressure become accurate measurements of altitude.
Ralph J Ralph J 28. Granted November 26, 1935. Why the difference?
US Patent 4,373,805: The official handbook of flying a plane, explaining the theory and practice of flight and all you need to know about your cockpit instruments. L adies and gentlemen, we are now cruising at 10,000 meters.