Which type of wind condition would shorten landing distance?

A headwind is a type of wind condition that would shorten landing distance because it helps to slow down the aircraft upon approach and landing. When an aircraft is landing, a headwind effectively increases the relative speed between the aircraft and the ground, providing additional lift and allowing for a shorter ground roll. The increased lift means that the aircraft can touch down at a higher airspeed without excessive increase in ground speed, leading to a more efficient landing phase.

In contrast, a crosswind may complicate the landing technique but does not inherently shorten the landing distance. A tailwind, on the other hand, would increase the ground speed of the aircraft upon landing, which typically extends the required landing distance, as the aircraft would not decelerate as quickly. Similarly, a downwind would also mean increased ground speed upon landing, creating a longer landing roll. Thus, a headwind, by providing increased lift and reducing the effective ground speed, directly contributes to a shorter landing distance.