Airspeed Readback to ATC

Tampa Approach Control: “Cessna 30D, maintain 130 knots.”


How would you read back that clearance?

Here’s what the AIM says:

4−4−7. Pilot Responsibility upon Clearance Issuance

b. ATC Clearance/Instruction Readback.

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. The read back 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.

What’s missing in this paragraph? There’s no mention of airspeed! I supposed you could argue that the AIM does include airspeed if you focus on its mention of vectors. Technically, vectors are a combination of direction and velocity. Although, the AIM provides this definition of vector in its Pilot/Controller Glossary.

“VECTOR− A heading issued to an aircraft to provide navigational guidance by radar.”

Um. So much for the heading and airspeed argument.

I guarantee you, if Tampa Approach says, “Cessna 30D, maintain 130 knots,” and you respond with your call sign only, Tampa Approach is going to insist on a readback of your speed assignment. Citing the appropriate passage in the AIM to the controller is not going to help your cause.

Fine, I’ll Read Back Airspeed Assignments

Tampa Approach Control: “Cessna 30D, maintain 130 knots.”

You: “Cessna 30D, 130.”

Good, right? After, all the AIM tells you to read back “the numbers”. Excuse me. I’ve got to go take some antacid for my AIM heartburn.

Okay, I’m back. The AIM says, “The read back of the ‘numbers’ serves as a double check,” blah, blah, blah. What the Government meant to say was, “The read back of the ‘numbers’ plus the applicable unit,” blah, blah, blah. Let’s put it in context.

Tampa Approach Control: “Cessna 30D, maintain 130 knots.”

You: “Cessna 30D, maintain 130 knots.”

Tampa Approach Control: “Cessna 30D, reduce speed to 110.”

You: “Cessna 30D, reducing speed to 110.”

Why Including a Unit is Important

I guarantee you, at some point in your flying career you’ll hear this radio exchange between ATC and another pilot:

ATC: “Lear 78M, turn right heading 180. Reduce speed to 170.”

Pilot of Lear 78M: “Lear 78M, 180, 170.”

Does that conform to AIM guidance? Yes it does. Is it a smart readback? I don’t think so. Will he turn to 180 degrees or 170 degrees? Will he maintain 170 knots or 180 knots? Who knows? A safe and coherent readback does not generate question marks.

The Takeaway

When ATC gives you an airspeed assignment, read back the number and add “speed” or “knots”. If the controller says “speed” include “speed” in your read back. If he says “knots”, read back “knots”. It only takes just a couple extra calories and a few milliamps of brain power to make one of those words come out of your mouth. The extra effort provides, as the AIM says, “a means of mutual verification.”

Good stuff? There’s more in my new book, Radio Mastery for IFR Pilots, available soon at


Reading Back a Final Approach Clearance

When giving you final instructions to intercept an instrument approach, an air traffic controller uses a very specific format. This format is:




Clearance to fly the specific approach

Thank goodness this forms an acronym. We can’t fly without a proper acronym. PTAC, pronounced “Pee tack”, gladdens our aviator’s heart. Let’s look at an example of how it’s applied.


The VOR Runway 18 approach at Madison.

Somewhere in South Central Wisconsin, An Airplane Buzzed By

You are being radar vectored to the straight-in VOR Runway 18 approach at Dane County Regional-Truax Field in Madison, Wisconsin. Madison Approach currently has you on a right base leg, 10 DME northwest of the VOR. The approach controller says, “Cessna 30D,”

(P) Position: “7 miles from HERRS.”

(T) Turn: “Turn right, heading 150.”

(A) Altitude: “Maintain 2,600 until established on the final approach course.”

(C) Clearance for the specific approach: “You’re cleared for the VOR Runway 18 straight-in approach.”

The AIM Read Back

What is the required read back for this clearance? According to the AIM, you need to read back “the numbers”, plus an acknowledgment you have been cleared for an approach. In this example, you would read back the TAC in PTAC. This includes your assigned heading, altitude, and that you have been cleared for an approach. There is no mention anywhere in the AIM that you must read back the name of the specific approach.

Before I give you the AIM’s recommended read back, I want to point out I don’t personally endorse this method. I’ll tell you how I would do it afterword. Taken literally, here’s how the AIM’s version of a readback would sound:

“Cessna 30D, 150, 2,600, cleared for the approach.”

My opinion on this? It’s an incomplete read back. It’s not smart.

My Read Back Technique

Here’s how I would read back this clearance. By the way, my technique is not original. It’s used by pilots around the world.

“Cessna 30D, right heading 150. Maintain 2,600 till established on the final approach course. Cleared for the VOR Runway 18 straight-in approach.”

My version allows the approach controller to do a complete check of my understanding of the clearance. By listening to this complete read back, he can assure I am going to:

1. Turn in the proper direction.
2. Fly a heading of 150 and not 150 knots. (Don’t laugh. Pilots have applied headings to their airspeed indicators.)
3. Maintain 2,600 until I line up on the VOR approach’s centerline.
4. Fly a straight-in using the course guidance for the VOR approach, as opposed to the RNAV Runway 18 or the ILS Runway 18.

Incidentally, at 10 miles from the runway, an aircraft on the VOR Runway 18 final approach to Madison will be 1.83 miles west of the ILS final for the same runway. (See the comparison of the 2 final approach courses below.) Do you think it might matter to ATC how you navigate to the runway when the 2 final approach courses are so vastly different? Of course it does.


The VOR final approach course is 171. The ILS final approach is 182. At 10 miles from the runway, the 2 final centerlines are separated by 1.83 NM.

Why the AIM Guidance Falls Short

This is why I think only saying, “Cleared for the approach” is so anemic. It gives ATC no chance to fully check how you plan to intercept the approach. It doesn’t even provide assurance you are going to fly the correct approach.

What You Can Do with this Information

The 2 most important takeaways from this example are,

1. ATC will always give you a final approach clearance using the PTAC format. It’s something you can hang your hat on, especially if you struggle with absorbing a complex clearance.

2. When reading back a final approach clearance, go beyond the AIM’s simplified (incomplete) guidance to read back the numbers. If you want ATC to check your understanding of a clearance, repeat that clearance verbatim.

Did you find this article helpful? If so, you can find an expanded version, plus more valuable techniques, in my new book, Radio Mastery for IFR Pilots. The book will be available soon at

PS: Want to know how I calculated there is 1.83 NM of separation between the VOR and the ILS final approach course in this example? Take a look at this discussion of the 60:1 Rule and how it applies here.


The Launch of IFR Flight Radio

Are you:

  • Working on your instrument rating?
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  • Looking for something better than the Aeronautical Information Manual to explain IFR radio procedures?
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Here is your go-to-source for IFR radio communication procedures and techniques.

In the coming weeks and months, I’ll have articles, podcasts, interviews, and graphical explanations to answer all of your questions about IFR radio work.

Stay tuned!

Jeff Kanarish