ATC clearances vs instructions
| ATC clearance | ATC instruction | |
|---|---|---|
| Meaning | Authorization to proceed under stated conditions | Directive to do or not do something now |
| Examples | Cleared to enter a zone, cleared for takeoff, cleared to land | Turn left, hold short, maintain 3,500 |
| Wording | Some form of "clear" | Worded to be readily identified; "instruct" seldom used |
| Duty | Comply once accepted, not merely received (CAR 602.31(1)(b)); acknowledging = acceptance | Comply and acknowledge, if safety of aircraft not jeopardized (CAR 602.31(1)(a)) |
(Definitions and acceptance: TC AIM RAC 1.6)
Clearance problems:
- Cannot comply with accepted clearance: tell ATC at once; clearance may be changed or cancelled (TC AIM RAC 1.6).
- Comply as best as possible, take any immediate action required, advise ATC as soon as possible. Never say nothing, never disregard (PSTAR 10.03, 10.04).
- Unacceptable clearance: refuse, tell ATC intentions, request amended clearance (PSTAR 10.06; TC AIM RAC 6.1).
Scope:
| Topic | Rule | Ref |
|---|---|---|
| Controlled aerodrome | Clearance needed to taxi, take off or land, by radio or visual signal | CAR 602.96(3)(g) |
| Airspace | Valid only in controlled airspace. Crossing into uncontrolled airspace: terrain and obstacle clearance back on pilot | TC AIM RAC 1.6 NOTE |
| Traffic | ATC works from known traffic only. Clearance or instruction does not relieve pilot of traffic avoidance and good airmanship | TC AIM RAC 1.6 |
Timing:
| Trigger | Duty | Ref |
|---|---|---|
| Instruction | Comply as soon as safely able; report any delay in taxiing or landing | Self-Paced Recency Q42 |
| Instruction with "NOW" | Immediately if safe, otherwise tell ATC | NAV CANADA VFR Phraseology, Circuit |
| "Report reaching," "report leaving," "report passing" | Also complied with | CAR 602.31, TC AIM RAC 8.3 |
- Takeoff delay: see Takeoff clearance, aborts, departure instructions and runway use.
Deviating from clearance or instruction allowed for (TC AIM RAC 6.0; CAR 602.31(3)):
- Emergency needing immediate action
- GPWS warning
- Wind shear warning
Other:
- ACAS/TCAS RA: see TCAS/ACAS RA response and phraseology.
- After deviating: advise ATC as soon as possible, return to last clearance or instruction (TC AIM RAC 1.6).
Weather: if severe enough to need immediate deviation with no time for ATC approval, pilot may use emergency authority to deviate, then advise ATC of flight alteration as soon as practicable (TC AIM MET 1.3.8).
Trap: clearance = permission accepted, instruction = order; "received" is not "accepted".
References
- CARs 602.31
- CARs 602.96(3)(g)
- TC AIM RAC 1.6
- TC AIM RAC 6.0
- TC AIM RAC 6.1
- TC AIM RAC 8.3
- TC AIM MET 1.3.8
- NAV CANADA VFR Phraseology, Circuit
- 2025-2026 Self-Paced Recency Study Program Answer Key
- TP 11919 PSTAR 10.0