Learning Objective 071.02.07.02.02: Describe the precautions to be taken when wind shear is suspected at take-off and approach.

WINDSHEAR: Descent and approach

• When wind shear conditions are anticipated, the approach and landing should be delayed until conditions improve, or the aircraft should divert to a more suitable airport.
• Select the most favourable holding point, approach path and runway, considering the location of the likely wind shear condition, and the available runway approach aids.
• Select less than full flaps for landing (to maximize the climb gradient capability and provide a wider margin between stall and flap overspeed) and adjust the final approach speed accordingly.
• If an ILS is available, engage the autopilot for a more accurate approach tracking.
• Closely monitor the airspeed, speed trend and ground speed during the approach to detect any evidence of imminent wind shear. If the presence of wind shear is confirmed, be prepared for a possible missed approach and escape maneuver.

If the aircraft passes through a windshear line from a tailwind to a headwind component, the inertia of the aircraft results initially in an increased airspeed and a deviation above the glidepath. The pilot's instinctive power reduction can result in the aircraft being short of power with a high rate of descent as the glidepath is approached and the effect of the inertia is lost. A rapid increase of power is now required if the aircraft is not to sink below the glidepath at a dangerously low altitude.

The aircraft should be stabilised by a certain point on the approach, but that is up to the procedures followed, and being stabilised by 800ft is an arbitrary value, so is not correct.