The Traffic Pattern / Circuit
- Standard circuit direction: Left-hand pattern — all turns to the left — unless stated otherwise in NOTAM, AIP, or chart (right-hand circuits marked with "RH" on aerodrome charts).
- Standard circuit height — light aircraft: 1,000 ft AAL (Above Aerodrome Level). Some airfields use 800 ft.
- Helicopter circuits: Typically 500–700 ft AAL, flown closer in to the runway than fixed-wing.
- Jet / turbine circuits: Often flown at 1,500 ft AAL with a wider pattern to allow for higher speeds and larger turning radius.
- Right-hand circuit: Used when terrain, controlled airspace, or noise considerations make the standard left-hand pattern impractical.
Checking Circuit Direction
Always consult the AIP aerodrome chart or airport information before flying. Circuit direction and height may differ from standard at specific aerodromes. NOTAM may impose temporary changes.
Circuit Legs — How to Fly the Traffic Pattern
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Upwind
(Takeoff leg)Climb on runway heading after takeoff. Retract gear after positive rate of climb confirmed. Retract flaps after obstacle clearance. Climb to circuit height before crosswind turn. Maintain runway centreline extended. -
CrosswindFirst turn, 90° to runway heading. Level off at circuit height. Check for other traffic joining downwind. Keep turns coordinated. Crosswind leg is typically short — judge timing based on aircraft type and wind.
-
DownwindFly parallel to the runway in the opposite direction of landing, maintaining circuit height. Complete pre-landing checks (BUMFISH / GUMPS or operator checklist). Abeam the threshold: begin configuring — reduce power, select approach flap. Start gentle descent.
-
BaseTurn 90° toward the runway. Configure for approach — gear down and locked (confirm 3 greens), select further flap. Adjust power to achieve target descent rate. Check wind effect and adjust base leg length accordingly to avoid overshooting or undershooting final.
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FinalRoll out on extended runway centreline. Select full flap (unless restricted). Establish and maintain stabilised approach speed. Use PAPI/VASI for glidepath reference. Aim for threshold — if not stable and on profile by 500 ft AGL, go around.
Stabilised Approach Criteria
By 500 ft AGL on final, the aircraft should be configured, on speed (±5 kt), on glidepath, and on centreline. If any parameter is outside limits — go around. Do not attempt to salvage an unstabilised approach.
BUMFISH Pre-Landing Check
Common UK mnemonic used on downwind leg prior to landing. Different operators use GUMPS or aircraft-specific checklists — always follow your specific checklist.
B
Brakes
Check brake pressure / operation
U
Undercarriage
Down and locked — 3 greens confirmed
M
Mixture
Rich for landing (piston aircraft)
F
Fuel
On correct tank; electric pump on if required
I
Instruments
Altimeter set QFE or QNH; DI aligned
S
Switches
Landing lights on; beacon/strobes as required
H
Hatches & Harness
Doors and windows latched; harness secure and tight
Aircraft Categories & Approach Speeds
ICAO aircraft categories are based on 1.3 × Vstall in the landing configuration (Vso). The category determines approach speed limits on instrument approaches.
| Category | Vstall (Vso) | Final Approach Speed | Max Circling Speed | Example Types |
|---|---|---|---|---|
| Cat A | ≤90 kt | 70–100 kt | 100 kt | C152, PA-28 Warrior, C172 |
| Cat B | 91–120 kt | 85–130 kt | 135 kt | C172 (heavy), PA-34, King Air |
| Cat C | 121–140 kt | 115–160 kt | 180 kt | Light jets, Citation, EMB-135 |
| Cat D | 141–165 kt | 130–185 kt | 205 kt | Business jets, B737, A320 |
Category Determines Minimums
Instrument approach plates publish separate minima for each aircraft category. Always use the column matching your aircraft's certified category. Flying a higher category's minimums is not permitted (it implies higher speed and wider approach path).
PAPI & VASI Approach Slope Indicators
PAPI — Precision Approach Path Indicator
4 lights, read left to right. Standard glidepath: 3° (same as ILS glideslope). Sited to provide 50 ft threshold crossing height on the correct glidepath.
W W W W — Too High
Significantly above the glidepath. Reduce power and increase rate of descent. Potentially dangerously high.
W W W R — Slightly High
Just above glidepath. Small reduction in power, allow glidepath to be recaptured from above.
W W R R — On Glidepath
Correct 3° glidepath. Maintain power and pitch. Threshold crossing height approximately 50 ft.
W R R R — Slightly Low
Just below glidepath. Add power, increase pitch slightly to arrest descent and recapture glidepath.
R R R R — Too Low / Dangerous
Significantly below glidepath. Apply full power immediately. Consider go-around if altitude is marginal.
Memory Aid
"White over red — you're ahead (of slope); Red over red — you're dead; White over white — you'll be out of sight." The correct picture is always two white, two red (W W R R).
VASI — Visual Approach Slope Indicator
Older 2-bar system found at many smaller aerodromes. Uses near bar and far bar of lights:
- Far bar White + Near bar Red: On glidepath — correct picture.
- Both bars White: Above glidepath — too high.
- Both bars Red: Below glidepath — too low, add power.
Estimating Glidepath Without PAPI
- 1-in-60 rule (3° glidepath): For every 1 nm from threshold, target approximately 300 ft above aerodrome elevation. At 3 nm you should be at circuit height (1,000 ft + elevation). At 6 nm, approximately 1,800 ft.
- Descent rate check: At 90 kt groundspeed on a 3° glidepath, the required rate of descent is approximately 480 fpm. At 120 kt: approximately 640 fpm.
- Runway visual cues: If the runway shape appears to be shortening (squashing) you are above glidepath; if it appears to be lengthening (stretching) you are below.
- Aim point: Pick a fixed aim point on the runway. If it moves up in the windscreen you are undershooting; if it moves down you are overshooting.