How to Read Back ATC Instructions in Spite of AIM Guidance

Turn right heading 110. Maintain 120 knots.

Here’s a paragraph from the Aeronautical Information Manual (AIM) talking about reading back ATC instructions: “The readback of the “numbers” serves as a double check between pilots and controllers and reduces the kinds of communications errors that occur when a number is either “misheard” or is incorrect.” (AIM 4-4-7b.) It’s a good and accurate statement, but it leaves something out.

What’s missing from the sentence in the AIM?

Units, expressed as a noun or verb, such as “Heading,” or “Knots.” Here’s an example that illustrates the problem.

ATC: “Cessna 57 Mike, traffic you’re following is twenty knots slower. Turn right heading one one zero.”

Pilot: “Cessna 57 Mike, one one zero.”

My question to you is this:

Is the pilot of Cessna 57 Mike turning to a heading of 110 degrees, or is he slowing to 110 knots to stay behind the preceding aircraft? He is following the AIM’s guidance to repeat the numbers. You might say common sense applies here, and the pilot is turning to 110.

Let’s blur the line a little more.

ATC: “Piper 38 Uniform, turn right heading one one zero to intercept final. You’re cleared for the visual approach, Runway One Four. Maintain one two zero knots until a five mile final.”

Pilot: “Piper 38 Uniform, one one zero, one two zero. Cleared the visual to One Four ”

You might say, “C’mon! No one talks like that on the radio.” I’m here to tell you, I hear read backs on the radio like this all the time.

The Solution

The solution is simple. Read back numbers and their associated units. Controllers are always required to say the numbers and a unit. (J.O. 7110.65T, Chapter 2-4-17.) You should too.

If the controller says “Heading one one zero,” read back “Heading,” plus the numbers.

If the controller says, “Maintain one two zero knots,” read back the numbers, plus “knots.”

The AIM only says “readback of the numbers.” It never says read back the number and the associated units or noun. There are some examples of pilot radio transmission in the AIM that include numbers and units, but the concept is never explained. Flyer beware.

Up Next

A rule breaker: You will never hear a controller say “Maintain altitude 3,000.” What should they say, and how should you respond? That’s coming up.

{ 3 comments… read them below or add one }

MT March 3, 2011 at 12:12 am

One other clue to help distinguish a heading clearance from the others is a reason for a vector must be included
7110.65T 5-6-2. METHODS
b. When initiating a vector, advise the pilot of the purpose.

VECTOR TO (fix or airway).
or if the pilot does not have knowledge of the type of approach,


JeffKanarish March 3, 2011 at 12:25 am

Excellent point! I missed that. Thank you for pointing it out.



Consultant ISO April 21, 2016 at 12:28 am

Ah, thankyou, Capt! I still trying to learn aout atc instructions.


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