Water on the Runway and Landing Performance

Dynamic Hydroplaning 

Most user-error aviation accidents occur on takeoff and landing. One factor to take into consideration when landing is the environmental conditions of the runway. If the runway is wet or icy, the pilot landing the plane has a risk of hydroplaning, which can lead to loss of effectivity of brakes and even lead to loss of directional control.  There are a few different strategies used to combat this potential hazard.

Mitigation Strategies

Some runways are grooved to drain excess rainwater. While this is usually not the case, it is a somewhat effective strategy to prevent potential water related mishaps. Another strategy used by pilots and air traffic controllers, is landing into the wind and slope of the runway. When mechanical braking cannot be completely counted on, aerodynamic braking can be used as a supplement. Another important factor to take into consideration is tire pressure. There is a simple calculation pilots can utilize to determine the minimum speed at which their aircraft will begin to hydroplane. Take the square root of the main gear tire pressure in PSI, and multiply it by 9. The product will be the slowest airspeed (in knots) at which the aircraft would begin to hydroplane. For example, if your tire pressure is at 49 PSI, you would take the square root of that (7), and multiply it by 9, making the minimum hydroplane speed 63 knots. 

Similar to driving on the highway, you must take into consideration the road conditions. There are many useful strategies to avoid mishaps, and if utilized properly, can maximize safety. 

Federal Aviation Authority. (n.d.). Chapter 11 - Aircraft performance. FAA. Retrieved From            https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/phak/13_phak_ch11.pdf