Clearance Readback Reversal and a Premature “Readback Correct”
At clearance delivery in a Cessna 182T, you receive: “Cessna 182T, cleared to Podunk via Springfield VOR, then as filed, climb 4,000, expect 6,000 10 minutes after departure, departure frequency 125.7, squawk 4271.” You read back: “Cleared to Podunk via Springfield, then as filed, climb 6,000, expect 4,000 10 minutes after departure, departure 125.7, squawk 4271, Cessna 182T.” The controller, busy with several strips, replies “readback correct” and switches to another aircraft. You are number three for departure, the weather is VFR, and your planned cruise altitude is 6,500. You believe the initial altitude and expected altitude may have been reversed in your readback. You must decide whether to accept the clearance as read back, query it, or wait until departure, and how to phrase the query without delaying the sequence unnecessarily.
1. Identify the discrepancy and explain why the controller’s “readback correct” does not make the clearance valid.
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The original clearance was climb 4,000, expect 6,000; your readback reversed them to climb 6,000, expect 4,000. The controller’s “readback correct” acknowledges your incorrect readback but does not amend the clearance. A clearance is amended only by an explicit amended clearance from ATC, not by a mistaken readback or a controller’s failure to catch it. If you fly the readback, you may climb to an altitude that conflicts with traffic, and ATC may base separation on 4,000. The discrepancy must be resolved before you leave the ground. “Readback correct” is not a substitute for a correct readback; it is a hearback error waiting to happen.
2. Compose the query to clearance delivery and state what you will do if no clarification is available.
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Key the microphone: “Clearance, Cessna 182T, verify initial altitude and expected altitude. I read back climb 6,000, expect 4,000; my clearance was climb 4,000, expect 6,000. Confirm which is correct.” This states the discrepancy, gives both versions, and asks for verification rather than arguing. If clearance delivery cannot clarify, hold your position and ask ground control to relay or request that you call clearance again. Do not depart with an unresolved altitude clearance; if the frequency is too busy, wait for a gap. If no clarification is possible before departure, do not accept the clearance-remain parked and resolve it.
3. What operational risks arise if you accept and fly the erroneous readback?
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Accepting the erroneous readback could put you at 6,000 feet when ATC expects 4,000, creating a traffic conflict and a possible near miss. It also sets a latent error: you may level at 4,000 later because you “expect” it, while your clearance was 6,000. The controller may not catch the reversal because “readback correct” was automatic. Defenses include writing the clearance on a pad, reading it back item by item, and comparing the readback to the original. If a controller says “readback correct” but you know your readback was wrong, challenge it. Use the full callsign and ask for verification rather than assuming the controller heard the error.