Read back requirements

Read back requirements

A read back is a repetition of the transmission using the same words and the same sequence, concluding by the aircraft call sign.


OO-ABC, turn right heading 240 and descend to 3000 feet

Turning right heading 240 and descending to 3000 feet, OO-ABC

Strict adherence to read back procedures ensures:

  • that clearance has been received correctly;
  • that clearance was transmitted as intended;
  • that the right aircraft, and only that aircraft, will take action on the clearance.

The following shall always be read back:

  1. ATC route clearances.
    Note – an ATC route clearance is NOT an instruction to take off or the enter an active runway.
  2. clearances and instructions to enter, land on, take off from, hold short of, cross and backtrack on any runway.
  3. runway-in-use, altimeter settings, SSR codes, level instructions, heading and speed instructions and, whether issued by the controller or contained in ATIS broadcast, transition levels.

Other clearances or instructions, including conditional clearances, shall be read back or acknowledged in a manner that clearly indicates they have been understood and will be complied with.

The controller shall listen to the read back. If the read back is incorrect, he/she shall transmit the word ‘NEGATIVE I SAY AGAIN’ followed by the correct version of the clearance or instruction.

In case of doubt about the pilot being able to comply with the clearance or instruction, the ATCO may say ‘if unable’ followed by an alternative.

If the pilot is unable to comply  with a clearance or instruction, they should advice the controller using the phrase ‘UNABLE’ and give the reason.

Communications tips for a correct read back:

  • Do not read back clearances as questions
  • Check radio communication and frequency if there is a prolonged break in activity on frequency
  • When reading back a conditional clearance, state the condition first
  • Set the clearance given, not the clearance expected
  • If you are unsure -always check