Pilots often use non-standard-phraseology for readbacks. Some examples:

ATC: DLM, switch to tower, 121.2

P: tower, for DLM


ATC: DLM, identified, climb via the RIDA9 departure

P: roger, climb via, DLM


DLM, cleared for takeoff runway 17

P: cleared for takeoff, DLM

The last two example are from two videos by Boldmethod, How To Fly An IFR Departure Procedure With A "Climb Via" and How To Fly An Instrument Arrival Procedure (STAR), used by an ExpressJet-pilot.

Especially the two last ones were a bit shocking to me when I heard a professional pilot using them. So I now want to ask, how far is this "ATC-Slang" allowed to go?

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    $\begingroup$ The shortest I have heard was double tapping the push-to-talk without any spoken words as an acknowledgement... $\endgroup$ Jun 16, 2018 at 13:20
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    $\begingroup$ Yes, the "double tap" is valid when the response is "OK", like when ATC says "N12345, current information is LIMA". You can't "double tap" any IFR clearances (they must be read back) or things that require a response. $\endgroup$
    – Ron Beyer
    Jun 16, 2018 at 14:25
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    $\begingroup$ @RonBeyer So this is really valid? How does a double-tap sound on the radio? $\endgroup$ Jun 16, 2018 at 14:38
  • $\begingroup$ Closely related, maybe a dupe? $\endgroup$
    – Pondlife
    Jun 16, 2018 at 15:10
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    $\begingroup$ @NoahKrasser Only in limited use (basically instead of saying "affirmative" to informational calls, especially if you are doing something like short final and the controller calls out a wind shift). The controller hears it as two "clicks" over the radio. Usually though I will just respond with a portion of my tail sign, like "Zero-Five-Charlie" to let them know it was me. $\endgroup$
    – Ron Beyer
    Jun 16, 2018 at 16:03

1 Answer 1


ATC is required to always use standard phraseology, and tapes are randomly reviewed to verify this--and too many violations gets them pulled off for retraining. This makes sense since talking is literally their entire job and it could be with anyone from students to veterans, including people who don't natively speak the language.

Pilots can use whatever wording they want as long as ATC can understand what they're saying, which naturally leads to shortcuts. It saves time/effort and helps keep the frequency clear for others. In fact, if/how you abbreviate things is a sign to ATC of how experienced you are. If you read back "climb and maintain three thousand five hundred feet", they'll treat you a bit differently than if you say "up to three point five". Listen to a busy airport or approach on LiveATC and you'll pick up the patterns in just a few minutes.

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." --Antoine de Saint-Exupery


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