AIM 4-4-7 (b) says:

Pilots of airborne aircraft should read back those parts of ATC clearances and instructions containing altitude assignments, vectors, or runway assignments as a means of mutual verification.

As a student pilot soloing into class C airspace, on one flight ATC kept repeating everything back until I spoke it back to him. As I approached the airport he informed me of the bearing (12 o'clock) and distance to the airport until I acknowledged him (comms were pretty busy so I didn't initially repeat back his information).

Since then I've noticed that if I don't repeat back wake turbulence warnings verbatim they will repeat the warning until I do. With a traffic alert I repeat back immediately 'looking for traffic' because if I look first they'll keep repeating the warning.

Aside from AIM 4-4-7 is there any more specific guidance?

up vote 25 down vote accepted

ATC is, broadly speaking, required to ensure that pilots hear, understand, and acknowledge information that is delivered. The way they do that is via read-backs, and although the AIM mentions a few of the things that are required it's a good idea to read back anything that's important (If you're not sure, err on the side of "It's important"), with your aircraft callsign (No callsign? Doesn't count!).

What are some important things controllers usually expect you to read back?

  • Clearances (headings, vectors, altitudes, transponder codes, and radio frequencies).
    Like the AIM says, mutual verification.
  • Runway assignments, hold short instructions, line-up-and-wait, and takeoff clearances.
  • Taxi routes Instructions, ESPECIALLY runway crossings & hold-short instructions.
  • Wake Turbulence advisories.
  • Traffic point-outs.
    The magic words here, by the by, are "Negative Contact" and "Traffic In Sight".
    I think if you say "Tally Ho!" you're required to buy everyone on the frequency a bottle of 30-year-old scotch.
  • Instructions to "Maintain visual separation with" some traffic
    ATC is handing off collision avoidance responsibility to you as the pilot.
    They need to hear "Will maintain visual separation with" the traffic in question.
    They also need you to tell them if you lose visual contact.
  • Airport Point-Outs (Especially if there are several airports close to each other)
    You can also pre-empt this by calling the controller: "Cessna 12345 has Podunk Municipal in sight", possibly with a bearing and approximate distance.
  • Landing Clearances
    If you're in a busy pattern and they give you a sequence ("Number 3, cleared to land") they want to hear that part too.
  • That altimeter setting you get after a handoff.
    (I blame Don Brown for getting me into this habit, but it IS a good one unless the frequency is crazy)

This list is by no means exhaustive, but it's most of the big stuff.

  • I'd like to see a definitive list. I regularly don't read back altimeter settings or wake turbulence advisories with no ill effects. However which runway you're cleared for, hold short instructions during LAHSO operations and VFR departure clearance you might receive at a class C airport when talking to clearance delivery - those are critical items that you are absolutely required to read back accurately. Not sure what you mean by an "airport point-out". – seattle272SP Sep 29 '14 at 7:47
  • @seattle272SP The closest thing to a "definitive list" is in the AIM (Specifically, 4-3-18 when on the ground, and 4-4-7 when you're in the air). The list above includes those items plus ones the controllers where I am (metro NY) seem to like to hear. Re: airport point-outs, I thought this was self-explanatory from my example, but something like "Cessna 12345 do you have Podunk Municipal 3 O'Clock and 5 miles?" – voretaq7 Sep 29 '14 at 16:24
  • 1
    OK - FYI the phrase "point out" has a specific meaning among controllers and it doesn't mean pointing out an airport to a pilot. I've not heard a fellow pilot or CFI use it. – seattle272SP Sep 29 '14 at 21:46
  • @seattle272SP I'm aware of the specific meaning for controllers. There isn't really a phrase that fits here (It's not a "point-out" because it's not traffic cutting a corner of another controller's sector. It's not a "traffic advisory" because the airport is not traffic, and it's not an "airport advisory" because it's not related to field or airspace conditions) - if you can think of a better way to phrase it I'd welcome an edit as I agree the phrasing I used could be confusing :) – voretaq7 Sep 29 '14 at 22:05
  • I've never been expected to readback a wake turbulence advisory, nor an altimeter setting. Not even once. – Dondi Michael Stroma Feb 19 '17 at 19:13

This little quote from the AIM is the source of a lot of confusion for new pilots.

In 4-2-3 (c), the AIM also says:

c. Subsequent Contacts and Responses to Callup from a Ground Facility.

You should acknowledge all callups or clearances unless the controller or FSS specialist advises otherwise.
...
Acknowledge with your aircraft identification, either at the beginning or at the end of your transmission, and one of the words "Wilco," "Roger," "Affirmative," "Negative," or other appropriate remarks; e.g., "PIPER TWO ONE FOUR LIMA, ROGER."


Let me make it simple:

  • You should read back those items that the AIM 4-4-7 specifies (and that you quoted in your question). Basically any time that they give you a clearance or anything that contains a number.
  • You should acknowledge with at the bare minimum your aircraft call sign and preferably something that lets them know that you got their instructions/message and understand it, every time that ATC talks to you.
    • The one exception is after you have been handed off to the final controller on a PAR approach, you do not acknowledge their instructions. They come too fast and you will have your hands full (and they specifically tell you this after your initial contact.)

As a short aside, you should know that there is case law which says that even when a pilot reads back a clearance incorrectly, the controller is not legally obligated to listen or correct the pilot. They consider it the pilot responsibility to hear and understand all clearances. For instance:

Controller: Cessna 1234, descend and maintain 3,000 feet
Pilot: Cessna 1234, Roger, descend and maintain 2,000 feet
Controller: No response
Pilot: Descends to 2,000 feet because that is what he understood, and may now be violated for it.

That being said, most controllers are very good and catch mistakes like this that you may make, but I have heard conversations in the cockpit along the lines of "it must be right because they didn't correct me when I read it back" and this is a situation ripe for problems/violations. If there is ever a doubt, ask for clarification!

  • Please consider posting something about that case law as an answer on this question: Is it ATC's responsibility to ensure read backs are correct?. While the current answer addresses the asker's specific situation, you could provide a more general answer to the title question. – Jeffrey Bosboom Jul 28 '15 at 5:00
  • @JeffreyBosboom I wish that I had more time, but am at work and will be busy for a while, but you may want to take a look at this webpage and provide an answer of your own! – Lnafziger Aug 10 '15 at 15:55

Regardless of what the AIM says, the practical rule I've always been taught is "read back all instructions". In other words, if ATC is telling you to do something then you must read it back otherwise they have no way to know if you understood the instruction correctly and will do what they expect you to. This includes clearance, ground and airborne instructions.

ATC information on the other hand is not an instruction (e.g. traffic advisories) so you only need to acknowledge it. But you should also read back altimeter settings because they're essential for maintaining altitude and therefore separation correctly.

And ATC is often very good at giving student pilots extra attention so even if they wouldn't expect a readback in other circumstances, they may have made an extra effort in the case you mentioned to make sure there was no possible misunderstanding.

  • 3
    +1 for "read back all instructions". Your readback doesn't have to be verbatim (especially on a crowded frequency) - just enough to convey that you've heard and copied the information correctly. – voretaq7 Dec 22 '13 at 20:22

Not really an answer per-se, but I usually find it much easier to learn what NOT to read-back:

  • Weather information (except QNH (altimeter settings)), like wind speed/direction, etc
  • Time/hour/estimates (except EAT (expected approach time) when cleared to a hold)
  • Chatter (hey, it happens! don't read it back)

I can't seem to think to any others, though there should be a couple more. Anything else that doesn't fall into this will get a readback from me.

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