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Navigation

Radio frequencies are subject to frequency protection. Therefore, you must be

below a certain altitude and within a certain distance before you can use the

frequency.

But are you allowed to call out anywhere? No, usually not,

But emergency breaks all rules, they say, so if you feel the situation is critical, do

not hesitate to call out and get a bearing. (When you do not know where you

are, you cannot know whether you are violating the law on frequency

protection).

9.9.1.4 Inaccuracy

The bearing you are given may have an inaccuracy. Inaccuracy is stated in classes.

Classes of inaccuracy: A: + or – 2 degrees
B: + or – 5 degrees

C: + or – 10 degrees

D: worse than C

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9.9.2 ADF and radio beacons (NDB and locators)

ADF (Automatic Direction Finder), or the radio compass, is an old navigation

system. Locator and NDB are the name of the beacons.

A direction finder, ADF, is mounted in the aircraft. It points out the direction to

radio beacons placed on the ground. The instrument in the airplane shows a

bearing relative to the nose of the heading of the airplane.

Frequency and range can be found on the back of the ICAO chart.

These beacons can be:
- NDB (Non Directional Beacons)

- Locator (L)

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 873