Circuit height under a low ceiling
A low ceiling in a control zone squeezes the circuit between two limits:
| Limit | Value | Cite |
|---|---|---|
| Below cloud | 500 ft | CAR 602.114(c) |
| Above surface | 500 ft (a floor, except taking off or landing) | CAR 602.114(d) |
- Ceiling = height above ground of lowest broken or overcast layer (AC 100-001).
- Highest altitude = field elevation + ceiling - 500 ft.
- Ceiling 1,000 ft leaves one height: 500 ft AGL.
- Example: field 400 ft ASL, ceiling 1,000 ft overcast. Join at 900 ft ASL, not the 1,000 ft AAE standard circuit or a NOTAM height (TC AIM RAC 4.5.2).
Trap: "as high as possible without entering cloud" breaks 500 ft cloud clearance.
References
- CARs 602.114
- AC 100-001 glossary (ceiling)
- TC AIM RAC 4.5.2