# Commission Implementing Regulation (EU) No 923/2012 of 26 September 2012 laying down the common rules of the air and operational provisions regarding services and procedures in air navigation and amending Implementing Regulation (EU) No 1035/2011 and Regulations (EC) No 1265/2007, (EC) No 1794/2006, (EC) No 730/2006, (EC) No 1033/2006 and (EU) No 255/2010 (Text with EEA relevance), Division SERA.14075: Exchange of communications

Extent: E+W+S+N.I.

(a) Communications shall be concise and unambiguous, using standard phraseology whenever available.
(1) When transmitted by an aircraft, the acknowledgement of receipt of a message shall comprise the call sign of that aircraft.
(2) When acknowledgement of receipt is transmitted by an ATS unit to an aircraft, it shall comprise the call sign of the aircraft, followed if considered necessary, by the call sign of the ATS unit.
(b) End of conversation.
A radiotelephone conversation shall be terminated by the receiving ATS unit or the aircraft using its own call sign.
(c) Corrections and repetitions
(1) When an error has been made in transmission, the word ‘ CORRECTION ’ shall be spoken, the last correct group or phrase repeated, and then the correct version transmitted.
(2) If a correction can best be made by repeating the entire message, the phrase ‘ CORRECTION, I SAY AGAIN ’ shall be used before the message is transmitted a second time.
(3) If the receiving station is in doubt as to the correctness of the message received, a repetition either in full or in part shall be requested.
(4) If repetition of an entire message is required, the words ‘ SAY AGAIN ’ shall be spoken. If repetition of a portion of a message is required, the phrase: ‘ SAY AGAIN ALL BEFORE… (first word satisfactorily received) ’ shall be used; or ‘ SAY AGAIN… (word before missing portion) TO…(word after missing portion) ’ ; or ‘ SAY AGAIN ALL AFTER… (last word satisfactorily received) ’ .
(d) If, in checking the correctness of a read-back, incorrect items are noticed, the words ‘ NEGATIVE I SAY AGAIN ’ shall be transmitted at the conclusion of the read-back followed by the correct version of the items concerned.

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Source: https://www.legislation.gov.uk/eur/2012/923/annex/section/14/division/SERA.14075 (the official version)
Page: https://openlegislation.uk/eu-regulation-2012-923/annex/section-14/division-SERA.14075
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.