To assume a brace position or crash position is an instruction that can be given to prepare for a crash, such as on an aircraft; the instruction to "Brace for impact!" or "Brace! Brace!" is often given if the aircraft must make an emergency landing on land or water. There are many different ways to adopt the brace position, with many countries adopting their own version based on research performed by their own aviation authority or that of other countries. The most common in passenger airliners being the forward-facing seat version, in which the person bracing places their head against or as close as possible to the surface it is likely to strike (and in the process bending over to some degree), placing their feet firmly on the floor, and their hands either on their head or the seat in front. Types of brace position There are many different ways to adopt the brace position, with many countries adopting their own version based on research performed by their own aviation authority or that of other countries. There is commonality among all brace positions despite these variations. Forward-facing seat For a forward seated passenger wearing only a lap belt, common recommendations for the brace position include: Place your head on, or as close as possible to, the surface it is most likely to strike. (For example, the bulkhead or seat in front.) Bend forward at the waist to some degree to avoid jackknifing or submarining (sliding) forward in the seat and out from under the belt). Place both feet on the floor, either flat or on the balls of the feet. In the United Kingdom, the brace-for-impact position for forward-facing passengers was optimised following the Kegworth air disaster in 1989. In that incident, the pilot announced "Prepare for crash landing" 10 seconds before impact, and the resulting injuries—from both those who did and did not adopt the brace position—would later be studied. The UK Civil Aviation Authority funded an engineering–medical joint research team, led by Nigel Rock of Hawtal Whiting Engineering Consultants and Prof. Angus Wallace of the Nottingham University Hospital and aided by Wing Commander David Anton of the Royal Air Force Institute of Aviation Medicine. Crash data was supplemented by medical information from the University of Nottingham and testing at the Institute of Aviation Medicine. The work used mathematical modelling derived from the automobile industry to analyse the human