Final answer:
If an airplane experiences a wind shift from a tailwind to a headwind during final approach, the pilot must correct for the sudden loss of airspeed by increasing power and adjusting the pitch to maintain the glide slope.
Step-by-step explanation:
If an aircraft on final approach and on glideslope encounters a sudden change from a 20 knots tailwind to a 20 knots headwind, the pilot should be ready to correct for a sudden loss of airspeed and resultant decrease in lift. This situation demands immediate action to prevent the aircraft from falling below the glide slope.
Correcting for this involves increasing power (adding thrust) to compensate for the loss of airspeed and to maintain the desired descent rate. The pilot must also be prepared to adjust the pitch attitude to maintain the glide path.
From a physics perspective, the issue at hand is one of relative motion. The initial tailwind contributed to the aircraft's ground speed, necessitating less engine power to maintain the required approach speed. When the wind switches to a headwind, the ground speed decreases, and without an increase in engine power or pitch adjustment, the plane would slow down too much, potentially leading to a stall. Hence, the pilot must adjust the throttle and aircraft pitch to safely continue the landing procedure.