Module 3 - Phonetic Alphabet & Prowords
Readback and Correction
What you will learn
Safeguard a critical word or number by repeating it when needed and repair your own error with the published correction sequence.
Reliable radio work includes error recovery. Repeat important data when procedure or safety requires it, ask Say Again when reception fails and correct your own message openly rather than hoping the listener inferred the change.
IMO SMCP says a sufficiently important part of a message can be safeguarded by saying Repeat and giving that part again. This is not a claim that every routine sentence needs a full readback; follow the applicable procedure and concentrate verification on identity, position, channel, time, instruction or other critical data.
If you did not properly hear another station, use Say Again. If you made the mistake, say Mistake, then Correction, then the corrected part. Those two paths keep the source of the error clear.
After a correction, release PTT and listen. The receiving station may still need to repeat or confirm the changed group. A clean correction reduces ambiguity but does not prove that the final value was received.
Worked example
The harbour station says 'change to Channel one-two', but the final digit was masked by noise.
- 1Do not infer the channel from local habit.
- 2Ask Say Again channel so the station repeats the critical group.
- 3Repeat or acknowledge the verified channel in the form required by the operating procedure, then change only when clear.
Sense check: A requested repeat fixes a reception problem; Correction would wrongly imply that you made the original error.
Repair one wrong distance without hiding the change
You begin to report a position 2.4 nautical miles from Big Head lighthouse, then see that the checked distance is 2.1 nautical miles.
1. Mark the error
Say Mistake immediately so the listener does not retain 2.4 as the current value.
2. Introduce the correction
Say Correction, distance two decimal one nautical miles.
3. Listen for the result
Release PTT and be ready to repeat or confirm the corrected group if requested.
Sense check: The final message must contain one unambiguous current value: 2.1 nautical miles, not two competing distances.
Common mistake or limitation
- Repeating the new value without signalling that the earlier value was wrong.
- Using Say Again for your own error instead of asking the other station to repeat its message.
- Assuming that silence after a correction proves the changed value was understood.
Recap
- Safeguard critical data by repeating it when required or important to verify.
- Use Say Again when another station was not properly heard.
- Use Mistake, Correction, then the corrected part for your own spoken error.
- Listen for confirmation or a further request after the correction.
Optional quick check
Section 7 of 7
You said the wrong distance in your own message. Which sequence makes the repair explicit?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
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