What effect does a wet runway have on V1?

When considering the impact of a wet runway on V1, it is crucial to understand the relationship between runway conditions and aircraft performance during takeoff. V1 is the decision speed during the takeoff phase, beyond which the pilot must continue the takeoff even if an engine failure occurs.

On a wet runway, the friction between the aircraft's tires and the runway surface is notably reduced compared to a dry runway. This reduction in friction leads to an increased stopping distance for the aircraft in the event of an abort. To maintain safety and ensure that the aircraft can achieve the necessary performance during takeoff, V1 is adjusted downwards.

By reducing V1, pilots gain an additional margin of safety, allowing for a longer distance to stop should they need to abort the takeoff. This is particularly important on a wet runway, where any attempt to stop might take longer than anticipated due to the diminished traction. Thus, V1 is reduced to account for the increased risk associated with wet conditions.