Page 372 - PPL-engelsk 2025

Communication

4.3.1 The range of the radio

How far can you actually transmit with an aircraft radio, someone might ask. The

range of our transmissions via the aircraft radio increases as the altitude

increases, and the radio waves propagate in straight lines.

Therefore, a “line of sight” is required between the station and the aircraft.

You can calculate the range by finding the square root of the flight altitude in

feet and multiplying this by 1.23. The number you find is the range in NM.

Ex:

You are flying at 2500 feet. The range is then:

√2500 x 1.23 = 61.5 NM

Ex:

If the ground station is at 900 feet and the aircraft at 2500 feet MSL, we get:

(√(900 + √2500) x 1.23 = 98.4 NM

There are usually 2 questions on the theory test with range, so remember the

formula!

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Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 372