Which condition results in a factored landing distance of one additional mile?

The condition that results in a factored landing distance of one additional mile is associated with a wet runway. When a runway is wet, it reduces the friction available between the aircraft's tires and the runway surface, impacting the aircraft's stopping ability. As a result, additional distance is required for the aircraft to come to a complete stop after touchdown. This increased stopping distance translates into a longer landing distance overall, which is why the landing distance factor is adjusted accordingly.

In contrast, while ground fog, short runways, and low visibility can also pose challenges during landing, they do not specifically correlate to a fixed additional distance requirement like a wet runway does. Ground fog mainly affects visibility, and while that can complicate the landing process, it does not inherently affect the stopping distance. A short runway might necessitate a longer landing approach or different landing technique but does not add a mile to landing distance; it simply requires careful consideration of approach speed and configuration. Low visibility conditions influence how pilots perceive the landing environment but again do not directly result in an additional mile for landing distance.