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.
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.
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 Amazon.com.
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.