Traffic Circuit (Pattern)
Definition
The traffic circuit (also called the traffic pattern) is a standardized rectangular flight path flown around an aerodrome during VFR operations. It ensures that all aircraft arriving, departing, or conducting training remain predictable, visible, and safely separated in the vicinity of the airfield — especially where no control tower is present.
Purpose
- Maintain orderly and conflict-free flow of aircraft
- Provide a consistent structure for arrivals, departures, and training flights
- Allow pilots to visually monitor and sequence with other traffic
- Enable safe separation at non-controlled aerodromes
Standard Circuit Layout
The traffic circuit typically consists of the following five legs:
| Leg | Description |
|---|---|
| Upwind (Departure) | Extends straight out from the runway after takeoff |
| Crosswind | 90° turn left or right from upwind, perpendicular to runway |
| Downwind | Flown parallel to the runway in the opposite direction of landing |
| Base Leg | 90° turn from downwind toward the runway alignment |
| Final Approach | Aligned with runway, descending to land |
Circuit Direction
| Type | Meaning |
|---|---|
| Left-hand circuit | All turns are to the left (most common) |
| Right-hand circuit | All turns are to the right (must be published or instructed by ATC) |
Circuit Altitude
Radio Phraseology (non-towered example)
- “OE-CVC, joining left-hand downwind runway 27”
- “OE-CVC, turning base runway 27”
- “OE-CVC, final runway 27, full stop”
- “OE-CVC, departing straight out runway 27”
Special Considerations
- Flight schools, gliders, helicopters, and parachuting zones may have separate or offset circuits
- Noise abatement may require specific routing within or outside the standard pattern
- Runway in use is determined based on wind direction, ATIS, or ground observation
Right vs. Left Circuit Example
- Runway 09, left-hand circuit → downwind is to the north of the runway
- Runway 09, right-hand circuit → downwind is to the south
Joining the Circuit
- From overhead via Overhead Join
- Via visual reporting points
- Directly into downwind, base, or final (if permitted)
- Always report and monitor on the appropriate traffic frequency