O'Hare International Airport was the first to introduce deicing facilities at the runway, something which has now become commonplace. Aircraft now have more sophisticated deicing systems that can be used on the ground and in the air. Many modern civil fixed-wing transport aircraft, for example the Boeing 737, use anti-ice systems on the leading edge of wings, engine inlets, and air data probes, using warm air. This is bled from engines and is ducted into a cavity beneath the surface to be anti-iced. The warm air heats the surface up to a few degrees above freezing, preventing ice from forming. The system may operate autonomously, switching on and off as the aircraft enters and leaves icing conditions. Ground deicing technologies are also developing, and a newer technology is infrared deicing. This is the transmission of energy by means of electromagnetic waves or rays. Infrared is invisible and travels in straight lines from the heat source to surfaces and objects without significantly heating the space (air) through which it passes. When infrared waves strike an object, they release their energy as heat. This heat is either absorbed or reflected by the cooler surface. Infrared energy is continually exchanged between "hot" and "cold" surfaces until all surfaces have reached the same temperature (equilibrium). The colder the surfaces, the more effective the infrared transfer from the emitter. This heat-transfer mechanism is substantially faster than conventional heat-transfer modes used by conventional deicing (convection and conduction) due to the cooling effect of the air on the deicing fluid spray. Aircraft deicing vehicles have also improved since the accident, usually consisting of a large tanker truck, containing the concentrated deicing fluid, with a water feed to dilute the fluid according to the ambient temperature. The vehicle also normally has a cherry picker crane, allowing the operator to spray the entire aircraft in as little time as possible; an entire Boeing 737 can be treated in under 10 minutes by a single deicing vehicle. Airport runways are also deiced by sprayers fitted with long spraying arms. These arms are wide enough to cross the entire runway, and allow deicing of the entire airstrip to take place in a single pass, reducing the length of time that the runway is unavailable. Notable passengers Richard Lawson – film and television actor (survived accident) See also 1992 in aviation Aviation safety Icing conditions List of accidents and incidents involving commercial