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 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.
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.