Instrument rating · ACS IR.III.A
ATC Clearances
An IFR flight runs on clearances. This lesson covers copying, reading back, complying with and questioning them, and what changes outside radar.
Why this one matters
A clearance is an agreement between pilot and controller about where the airplane will be. Misunderstandings, copied wrong, read back carelessly, or meant for another airplane, are how airplanes end up at the wrong altitude near terrain or traffic. Clear copying and the habit of asking keep both sides of that agreement honest.
Can’t miss
- •Copy a clearance in order, CRAFT: Clearance limit, Route, Altitude, Frequency, Transponder code.(AIM, Chapter 4, Section 4 (ATC clearances))
- •Read it back from what you wrote, with your call sign: altitudes and altitude restrictions, headings and vectors, runway assignments in the order given, the code, and every hold-short instruction. If any part is unclear, ask.(AIM 4-4-7, 4-3-18)
- •Once cleared, deviate only with an amended clearance, in an emergency, or in response to a TCAS resolution advisory, and tell ATC as soon as possible. Never fly a clearance issued to another aircraft. If you can’t comply, say "unable" before you start. Outside Class A, in VFR conditions, you may cancel IFR.(14 CFR 91.123(a)-(c), (e))
- •Clearance void time: if you’re not off by then, tell ATC as soon as possible, and by the advise-by time ATC gives (never more than 30 minutes after the void time), or you're overdue and search starts. Departing after the void time means no IFR separation and may violate 91.173.(AIM 5-2-7; 14 CFR 91.173)
- •Report at all times (radar or not): vacating an altitude; an altitude change on a VFR-on-top clearance; unable to climb or descend at 500 fpm; a missed approach; a TAS change of 5% or 10 knots, whichever is greater; time and altitude reaching a holding fix or clearance limit; leaving a holding fix; any loss of navigation or communication capability (91.187); unforecast weather; anything else that affects safety.(AIM 5-3-3a.1; 14 CFR 91.183, 91.187)
- •Only when not in radar contact, add: position reports at compulsory reporting points; leaving the FAF or outer marker inbound on final; and a corrected estimate when the last one is off by more than 2 minutes (3 over the North Atlantic). Start these again when ATC says "radar contact lost".(AIM 5-3-2, 5-3-3a.2)
- •Checkride standard: airspeed ±10 knots, heading ±10°, altitude ±100 feet, course within ¾-scale CDI deflection.(Instrument Rating ACS (FAA-S-ACS-8C), IR.III.A.S5)
What you should know
Copying and reading back K1 · R1 · R4
- Write it in CRAFT order before you call: the clearance limit, route, altitude (and expected altitude), departure frequency and squawk.(AIM, Chapter 4, Section 4 (ATC clearances))
- Read back altitudes, headings, codes and restrictions. ATC listens for errors; you listen for your own call sign.(AIM, Chapter 4, Section 4 (ATC clearances))
- Similar call signs cause read-back mistakes. If you aren’t sure a clearance is for you, ask.(AIM, Chapter 4, Section 4 (ATC clearances))
- Clearance void times and "hold for release": you may not depart before release or after the void time without a new clearance.(AIM, Chapter 5, Section 2 (departure procedures))
- The workflow: copy it, read it back, then set it (altitude preselect, heading bug, frequencies, code, navigator route), then verify each against what you wrote and fly it within standards.(AIM, Chapter 4, Section 4 (ATC clearances); Instrument Rating ACS (FAA-S-ACS-8C), IR.III.A.S1-S7)
Complying, questioning and refusing R2 · R3 · K2
- Fly the clearance as issued. Don’t accept one your airplane can’t do, like a climb gradient it can’t meet or a route your equipment can’t fly.(14 CFR 91.123)
- If a clearance looks wrong (toward terrain, below the MEA), question it. On a radar vector, ATC's minimum vectoring altitude can legally be below the MEA; if you can't resolve it, say "unable" and ask for a corrected clearance. You remain responsible for the flight.(AIM, Chapter 4, Section 4 (ATC clearances))
- In an emergency you may deviate as needed. Tell ATC, and ask for priority when you need it. Two different reports may follow: a written report to the FAA if it asks (91.3(c)), and, if ATC gave you priority and asks, a detailed report within 48 hours to that facility's manager (91.123(d)).(14 CFR 91.3(b)-(c); 91.123(d))
Lost comms and non-radar K3
- Lost communications: squawk 7600 and follow 91.185 for route and altitude. The full procedure is in the Loss of Communications lesson.(14 CFR 91.185)
- Outside radar contact, give position reports at compulsory reporting points: identification, position, time, altitude, type of flight plan (unless talking to ARTCC), ETA and name of the next point, the one after, and remarks.(AIM, Chapter 5, Section 3 (en route procedures))
- The at-all-times reports apply in radar contact too; the non-radar list adds to them, it doesn't replace them.(AIM 5-3-3)
On the flight
ACS standards
- Maintain airspeed ±10 knots, headings ±10°, altitude ±100 feet; track a course, radial or bearing within ¾-scale deflection of the CDI.(Instrument Rating ACS (FAA-S-ACS-8C), IR.III.A.S5)
- Copy, read back, interpret and comply with ATC clearances in a timely manner using standard phraseology.(Instrument Rating ACS (FAA-S-ACS-8C), IR.III.A.S1)
What your instructor is watching for
Your instructor watches for a clean CRAFT copy, a complete read-back, radios and transponder set right, and the courage to say "unable" or ask.
Scenarios
Decide what you would do first, then see the worked answer.
You copy "climb and maintain 5,000" but you think you heard "50" in the other airplane’s call sign.
What do you do? See the worked answer
Ask: "Was that clearance for November 1234X?" Never fly a clearance you aren’t sure is yours.
AIM, Chapter 4, Section 4 (ATC clearances)
Your void time is 1430. At 1428 you’re still taxiing.
What do you do? See the worked answer
Don’t depart. Call ATC as soon as possible for a new clearance, by the advise-by time they gave.
AIM, Chapter 5, Section 2 (departure procedures)
ATC gives you a departure with a climb gradient you can’t meet on a hot day.
What do you say? See the worked answer
"Unable", and ask for another departure or a different runway.
14 CFR 91.123
Common mistakes
Reading back from memory.
Errors slip in.
Instead: Read back what you wrote.
Accepting a clearance you can’t fly.
You’re still responsible.
Instead: Say "unable" early.
Forgetting required reports.
ATC builds separation on them.
Instead: Know the "always report" list.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice atc clearances out loud with our examiner.
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Go to the source (free)
Teaching this? The instructor lesson plan →
Sources
- Aeronautical Information Manual (AIM): Chapters 4, 5 and 6
- Instrument Procedures Handbook (FAA-H-8083-16B): Departures; en route
- Instrument Flying Handbook (FAA-H-8083-15B): IFR flight; holding
- 14 CFR: 91.3, 91.123, 91.183, 91.185
- Instrument Rating ACS (FAA-S-ACS-8C): Area III
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.