Definition
An onboard radar-based system that scans ahead of the aircraft to detect wind shear conditions before the aircraft encounters them, providing the flight crew with visual and aural warnings of hazardous wind shear along the flight path, typically during takeoff, approach, and landing.
Plain English
A system on the aircraft that looks ahead and warns the pilots if dangerous shifting winds are coming up, giving them time to react before flying into them.
Context Anchor
Seen in aircraft systems, cockpit alerting, and takeoff or landing procedures for aircraft equipped with predictive wind shear warning capability.
Derivation
Predictive means looking ahead in time. Wind shear means a sudden change in wind speed or direction over a short distance. Together, the system 'predicts' the shear before the aircraft flies through it — distinguishing it from reactive systems that only detect shear once the aircraft is already in it.
Why Pilots Care
Wind shear can cause rapid loss of airspeed and lift; advance warning lets the crew execute a go-around or adjust the flight path before the condition is encountered.
Grounding Statement
Picture the airplane approaching a runway while the air ahead is suddenly changing direction and strength; PWS is the system that tries to warn the crew before they enter that air.
Intuition Check
PWS does not remove or control wind shear. It only warns pilots that wind shear may be ahead so they can take action.
Example Sentence 1
On final approach, the crew received a PWS warning and executed a go-around before entering the wind shear area.
Example Sentence 2
On departure the predictive wind shear system issued a caution as the aircraft climbed through 800 feet.