Chapter 3. Radar Vectors
Reading Back the Numbers is Not Good Enough
“Cessna 9130D, Harrisburg Approach, radar contact,” says the approach controller. “This will be radar vectors to the ILS Runway 8 at Lancaster. Continue your climb, climb and maintain 4,000.”
I read back, “Cessna 9130D, climb and maintain 4,000.”
“Cessna 30D, how will this approach terminate?” the controller asks. He is asking what we plan to do after this ILS.
“Cessna 30D will be low approach, followed by vectors for the VOR-A at Lancaster,” I say.
“Cessna 30D, I have your request. After the low approach, your climb out will be, fly runway heading, climb and maintain 3,000.”
I answer, “Cessna 30D, climb out will be fly runway heading, climb and maintain 3,000.”
“Cessna 30D, readback correct. Turn left heading 350,” say Harrisburg Approach.
“Cessna 30D, left heading 350.”
Notice how I read that clearance back to the controller. I know this seems like a simple clearance, but how I read it back is anything but simple. As a leaping off point, let’s go to the AIM to see how it describes clearance readbacks.
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.
This whole paragraph really sticks in my craw for a couple of reasons. First, it does not even mention the need to read back airspeed assignments or instructions regarding vertical speed. Some people would make the argument that a vector is a combination of heading and airspeed, so perhaps the AIM actually has airspeed covered with this paragraph. I think that argument is a stretch. You also don’t see any discussion of how to respond to “cleared for the approach” from ATC. We’ll get to that in a couple of minutes.
The second reason this paragraph stinks to high heaven is it fails to mention the need to read back the units associated with the numbers. The AIM says, “The read back of the ‘numbers’ . . .” Some pilots take this direction literally. Consider this exchange between ATC and a pilot:
ATC: “Lear 57E, turn right heading 180. Maintain 170 knots.”
Pilot: “One eight zero, one seven zero, Lear 57E.”
According to the AIM, this is a perfect readback because the pilot read back the numbers. According to me, this is a terrible readback because the pilot read back the numbers and nothing else.
A readback is an insurance policy you may apply with every clearance. By reading back ATC’s clearance, you give your air traffic controller the opportunity to evaluate your understanding of the clearance. If the controller detects a mistake in your readback, he will provide a correction.
The controller can only evaluate what you say, not what you think. Whatever you leave out of your readback is information that cannot be checked. In the example above, “One eight zero, one seven zero,” there is no way ATC can determine whether this pilot is about to turn to a heading of 180 degrees or a heading of 170. Will he reduce speed to 180 or 170 knots? We can’t tell, and neither can ATC.
When the FAA comes knocking on my door and says, “Jeff, will you help us edit the next version of the AIM?,” first, I’m going to scrape my jaw off the floor. Next, I’ll have a field day rewriting the section on pilot readbacks. The passage I submit will read:
Read back an ATC clearance exactly as it is given. If the controller gives you a direction to turn along with a heading, read back the direction of turn, the word ‘heading’ and the heading in degrees. For example, if the controller says, “Turn left, heading 350,” read back, after saying your call sign, “Left, heading 350.” If the controller tells you to turn a number of degrees, rather than to a specific heading, read back the number plus “degrees.” For example, “Cessna 30D, turn right 30 degrees.” Read back, “Cessna 30D, right 30 degrees.”
Most of the time, ATC will include the direction to turn when giving you a heading change. If the turn is small, such as 30 degrees of heading change or less, some controllers will not specify the direction of turn because the direction to turn is obvious. In that case, the controller may simply say “fly heading” right before he states the heading to fly in degrees. For example, “Cessna 30D, fly heading 340.”
For airspeed changes, the controller will say either “knots,” “speed,” or “airspeed.” Be sure to include the same term used by ATC when making your readback. For example, if the controller says, “Reduce to 120 knots,” read back, with your call sign, “Reducing to 120 knots.”
Occasionally, a controller will tell you to adjust your speed in relative terms. He might say, for example, “Maintain your best forward airspeed.” Other examples of clearances that address airspeed in relative terms include:
“Reduce to clean speed.” This means slow to the lowest speed that does not require flap extension. Your readback should be your call sign plus “reducing to clean speed.”
“Reduce to slowest practical speed.”—This means slow down as much as possible for the current flight conditions. Your readback should be your call sign plus “reducing to slowest practical speed.”
“Reduce to final approach speed.”—This means exactly what it sounds like. Your readback should be your call sign plus “reducing to final approach speed.”
If the controller needs you to climb or descend at a specific rate, he will include the words “feet per minute.” For example, “Maintain at least 1,000 feet per minute in your climb.” Read back, with your call sign, “We’ll maintain at least 1,000 feet per minute in our climb.”
A controller may also direct you to descend or climb at the highest rate possible for your aircraft. If so, he will say, for example, “I’ll need your best rate of descent/climb.” He may ask for the maximum rate through a specific altitude. If so, it would sound like this: “Maintain your best rate of climb through 5,000.” Your readback should be your call sign plus “best rate of climb/descent” and if given, the altitude specified in the clearance.
A controller will not usually say the word ‘altitude’ when telling you to change your altitude. He will say, “climb and maintain,” or, “descend and maintain” before saying the altitude. For example, ATC says your call sign plus “climb and maintain 5,000.” Your readback should include your call sign plus “climb and maintain 5,000.
Do you think I should hold my breath while waiting for the FAA to ask me to help with a rewrite of the AIM? I’m a fan of breathing, so it’s probably not a good idea.
“Cessna 30D, turn left heading 260, downwind,” says our approach controller.
“Cessna 30D, left heading 260.” I read back. The controller said this turn would place us on the downwind leg. I don’t need to read that back to him because it is an advisory message designed to help us build situational awareness.
I hope you did not conclude, based on what I just said about readbacks, the easy path is to simply repeat everything ATC says to you. You certainly may repeat everything you hear, but doing so would require more transmission time than necessary. Repeating everything like a parrot may also identify you as “amateurish” among those who take pleasure in categorizing others.
Fortunately, it isn’t difficult to distinguish between a clearance that does require a readback and advisory information that does not. A clearance requires you to change your aircraft’s flight path or speed. An advisory message does not require a change to your aircraft’s flight path or speed. You may choose to change course, altitude or airspeed based upon an advisory message, but ATC does not require it.
Consider these 2 transmissions from ATC.
- “Cessna 30D, turn right 30 degrees.”
- “Cessna 30D, moderate to extreme precipitation from your 11 o’clock to your 1 o’clock and 20 miles.”
Transmission 1 requires you to change heading by 30 degrees. This requirement should be read back and acted upon. ATC requires you to do nothing with Transmission 2 other than acknowledge you heard it. No requirement to do anything equals no readback. If you decide to change course, altitude, or airspeed based on an advisory, you must tell ATC what you plan to do before you do it.
With few exceptions, a controller is not required to give you advisory information. Most controllers will add advisory information, when appropriate, if they are not too busy. In general, the busier the controller, the more likely the controller will stick to the minimum required to get the job done.
I mentioned exceptions. A controller should tell you the reason for the first turn he gives to you. Earlier, you heard a reason for the clearance given to us when we first checked in with Harrisburg Approach. The controller said, “This will be radar vectors to the ILS Runway 8 at Lancaster.” You are going to hear controllers give other reasons for radar vectors in the next several chapters.
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