Wind Correction Angle Calculator
REF: NAV-WCA-CALC
Calculate the heading required to maintain your desired true course under crosswind conditions. Input your True Airspeed (TAS), desired course, and wind vector to compute your Wind Correction Angle (WCA) and estimated Groundspeed (GS).
> OUTPUT_NAVIGATION_DATA
HEADING TO FLY
083°
WIND CORRECTION
-7° (Left)
GROUNDSPEED
99 KTS
Wind Correction Angle Reference Chart
Estimated WCA for relative wind angles based on 100 KTS True Airspeed (TAS):
| Relative Wind Angle | 10 kts Wind | 20 kts Wind | 30 kts Wind | 40 kts Wind |
|---|---|---|---|---|
| 15° (Quartering) | ±1.5° | ±3.0° | ±4.5° | ±6.0° |
| 30° | ±2.9° | ±5.7° | ±8.6° | ±11.5° |
| 45° | ±4.1° | ±8.1° | ±12.3° | ±16.5° |
| 60° | ±5.0° | ±10.0° | ±15.0° | ±20.3° |
| 75° | ±5.6° | ±11.2° | ±16.8° | ±22.8° |
| 90° (Direct Crosswind) | ±5.7° | ±11.5° | ±17.5° | ±23.6° |
Understanding Wind Triangle & Drift
When an aircraft flies through a moving airmass, its path over the ground is a vector sum of its airspeed and the wind vector. To stay on a desired course line, the aircraft must crab into the wind by a specific angle—the Wind Correction Angle (WCA).
Key Principles:
- Wind Correction Angle Formula: WCA = arcsin((Wind Speed × sin(Relative Wind Angle)) / True Airspeed).
- Wind From Left: If the wind is blowing from your left, subtract the WCA from your desired course (Crab Left).
- Wind From Right: If the wind is blowing from your right, add the WCA to your desired course (Crab Right).
- Groundspeed Effect: Headwinds reduce your groundspeed relative to TAS, while tailwinds increase groundspeed. Pure crosswinds slightly reduce groundspeed due to the crab angle.
Pilot Note: Always remember that wind directions provided by ATIS/METARs are relative to True North for surface forecasts, while tower reports for takeoff/landing are relative to Magnetic North. Ensure units match when running calculations!