Airspeed can change even when the aircraft’s ground speed does not
Lift depends on airflow over the wings. If a strong headwind suddenly weakens or becomes a tailwind, indicated airspeed can fall before the aircraft has time to accelerate.
Microbursts create a particularly challenging sequence
A descending column of air spreads outward near the surface. An aircraft can encounter increasing headwind, then downdraft, then a strong tailwind in quick succession.
Modern aircraft can warn crews of wind shear
Predictive systems use weather radar information, while reactive systems detect the aircraft’s actual energy change. Warnings are designed to prompt an immediate standardized response.
Escape guidance prioritizes climb performance
During a wind-shear escape, pilots normally use prescribed thrust and pitch guidance rather than trying to maintain a normal speed or follow the planned departure path.
Airports also monitor local wind behavior
Low-level wind-shear alert systems and multiple wind sensors can identify hazardous changes around runways. Controllers pass those reports to arriving and departing crews.
Avoidance is preferable to recovery
If severe shear or a microburst is reported, crews may delay takeoff, hold, divert or go around. The best wind-shear maneuver is often not entering the hazard in the first place.
Wind shear is a rapid change in wind speed or direction
The change can occur horizontally or vertically and can quickly alter an aircraft's airspeed and flight path.
Low altitude is the most dangerous place for it
During takeoff or landing, crews have little height available to recover from a sudden loss of performance.
Microbursts can produce severe shear
Strong descending air beneath thunderstorms can spread outward near the ground, creating rapidly changing headwind and tailwind components.
Modern aircraft may provide predictive and reactive warnings
Weather radar and onboard systems can alert crews to conditions associated with dangerous shear, depending on equipment.
Escape guidance prioritizes aircraft performance
If severe wind shear is encountered, pilots follow trained procedures using appropriate thrust and pitch rather than trying to maintain the original approach path.
Avoidance is better than recovery
Airport sensors, weather reports and pilot observations help crews delay departure, go around or hold clear when dangerous shear is suspected.
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