Windshear

Windshear refers to a sudden and significant change in wind speed and/or direction over a short distance. It can occur horizontally or vertically and is particularly dangerous during takeoff, approach, and landing, when aircraft are close to the ground and have limited performance margins. Windshear can lead to loss of lift, sudden changes in flight path, and in severe cases, controlled flight into terrain (CFIT) or runway excursions.

• Thunderstorms and CB (Cumulonimbus) clouds
• Frontal zones, especially cold fronts
• Temperature inversions near the surface
• Mountainous terrain with mechanical turbulence
• Low-level jet streams
• Calm wind at surface, strong wind aloft

• Sudden loss or gain of airspeed
• Unexpected deviation from glide path
• Risk of stall or overspeed
• Go-around or missed approach may become necessary
• Aircraft may touch down short, float, or drift off centerline

• Onboard systems: Windshear warning and detection (GPWS, predictive windshear radar)
• ATC reports: Based on pilot reports (PIREPs), radar, or weather stations
• ATIS/ATC broadcasts:
  • “Windshear reported on final runway 34”
  • “Caution, windshear alerts in effect”

• “Windshear reported by departing Boeing 737, 15 knot loss at 400 feet”
• “OE-XYZ, caution windshear reported by landing traffic”
• “Windshear warning, go around, OE-ABC”

• ✅ Go around or abort takeoff if conditions are unsafe
• ✅ Follow windshear escape guidance if installed
• ✅ Apply TOGA power, maintain pitch attitude
• ✅ Avoid overcorrecting; stabilize aircraft energy
• ✅ Fly a slightly higher approach speed when windshear is forecast (with caution)

• Always brief for wind and weather on final approach
• Monitor ATIS and PIREPs for windshear or gust reports
• If in doubt, delay approach or divert
• Practice windshear recovery in simulators like LearnATC advanced IFR training

Some airports publish windshear procedures or advisories in their AIP AD section. Low-Level Windshear Alert Systems (LLWAS) may be active at major airports.