Water landing

In aviation, a water landing is, in the broadest sense, an aircraft landing on a body of water. Seaplanes, such as floatplanes and flying boats, land on water as a normal operation. Ditching is a controlled emergency landing on the water surface in an aircraft not designed for the purpose, a very rare occurrence. Controlled flight into the surface and uncontrolled flight ending in a body of water (including a runway excursion into water) are generally not considered water landings or ditching. Seaplanes, flying boats, and amphibious aircraft are designed to take off and alight on water. Alighting can be supported by a hull-shaped fuselage and/or pontoons. The availability of a long effective runway was historically important on lifting size restrictions on aircraft, and their freedom from constructed strips remains useful for transportation to lakes and other remote areas. The ability to loiter on water is also important for marine rescue operations and fire fighting. One disadvantage of water alighting is that it is dangerous in the presence of waves. Furthermore, the necessary equipment compromises the craft's aerodynamic efficiency and speed. Early crewed spacecraft launched by the United States were designed to alight on water by the splashdown method. The craft would parachute into the water, which acted as a cushion to bring the craft to a stop; the impacts were violent but survivable. Alighting over water rather than land made braking rockets unnecessary, but its disadvantages included difficult retrieval and the danger of drowning. The NASA Space Shuttle design was intended to land on a runway instead. Since 2020 the SpaceX Dragon has used water landings. The Boeing CST-100 is designed to do likewise. While ditching is extremely uncommon in commercial passenger travel, small aircraft tend to ditch slightly more often because they usually have only one engine and their systems have fewer redundancies. According to the National Transportation Safety Board, there are about a dozen ditchings per year.