Training and Safety Tip: The art of landing in the rain
You don’t have to have a degree in physics or be able to recite the definition of coefficient of friction to understand the effects of hydroplaning.
You’ve likely experienced those effects when driving your car in the rain. When you drive over pavement covered by pooling or standing water, the tires may lose contact with the road and skim on the water instead, reducing friction between the tires and the road surface to zero. This makes the car briefly uncontrollable.
There are a few things that pilots can do to mitigate the risk. For example, during your preflight inspection, make sure the tires are in good condition, paying attention to tread wear, and verify proper inflation.
When planning a flight, if you anticipate precipitation, look for a grooved runway at your destination. Grooved runways channel water away from the landing surface and therefore improve traction and mitigate the risk of hydroplaning. But there aren’t that many of these available to general aviation pilots. If you have a choice of wet or snow-covered runways, always try to land on the longest one.
When landing on a wet runway, focus on a stable approach that keeps your touchdown speed low (but not unsafely so), because the higher the speed, the more likely you’ll hydroplane. Be gentle with the brakes. If, upon landing and lowering the nose, you find the brakes are ineffective, lift the nose slightly to help slow the airplane without using the brakes. Maintain directional control of the airplane with the rudder. As soon as the hydroplaning ends you can gently apply brake pressure, but take care to avoid using more pressure than you need to. Hard or abrupt braking on a slick surface can cause a skid.
As with other types of flight scenarios, the pilot can improve safety by being prepared. More information about hydroplaning can be found in Chapter 9 of the FAA’s Airplane Flying Handbook.
