Readability scale and test procedures

Readability scale

The following readability scale is used to classify the quality of the transmissions:

Scale

Description

1

Unreadable

2

Readable now and then

3

Readable but with difficulty

4

Readable

5

Perfectly readable

Test procedures

When a test transmission is made, it should take the following form:

  1. identification of the aeronautical station being called;
  2. aircraft identification;
  3. the words “RADIO CHECK”; and
  4. the frequency being used.

Replies to test transmissions should be as follows:

  1. identification of the station calling;
  2. identification of the station replying;
  3. information regarding the readability of the transmission.

Any information that may be useful to the station making the test should be spoken after the readability of the transmission.

Example:

Test:  Greenville Tower, OO-ABC, radio check 118.925

Reply:   OO-ABC, Greenville Tower, reading you 3 with disturbing sharp sound

or:  OO-ABC, Greenville Tower, you are unreadable