Radiotelephony Library

Used to test the quality and readability of a radio transmission before departure, when establishing contact on a new frequency, or whenever the pilot suspects a radio malfunction. The pilot states the frequency being used so the ground station can confirm it is receiving on the correct channel.

• Readability is reported on a 1-5 scale: 1 (unreadable), 2 (readable now and then), 3 (readable but with difficulty), 4 (readable), 5 (perfectly readable).
• If readability is below 3, switch to the back-up frequency or request a different channel rather than continuing on a marginal link.
• Pilot read-back closes the loop — always end with your own readability assessment.
• RADIO CHECK is for INITIAL contact (you state the frequency so the station can confirm tuning). Once contact is established, the established-contact variant is HOW DO YOU READ — see the next topic.