LAUSR

OBJECTIVES In winter terrain parks special airbags are used for skiers and snowboarders to practice jumps and achieve safe landings. However, in 2010 two skiers landed at the end of oval airbags. One suffered fatal, the other severe, injuries. The aim of this study was to identify parameters that lead to jumping over the airbag and to suggest preventive measures. DESIGN Simulation study. METHODS For the calculation of the flight distance the equation of motion was solved for the jumper's approach and flight phase. Measured data of five jumps into an airbag employed in a similar geometry and conditions as in the second accident case were used to validate the simulation and to measure typical takeoff velocities. The effect of approach and takeoff parameters on the flight distance for oval and flat airbags was analyzed with the simulations. RESULTS In both accident cases a too long approach led to a too high takeoff speed, which was the cause for landing at the end of the oval airbags. The effect of flight distance is considerably more sensitive to approach and takeoff parameters with oval versus flat airbags. CONCLUSIONS Three measures are recommended to prevent jumping over an airbag. An approach corridor with top and lateral fences has to be set up and the approach should be steep. Flat airbags are preferable to oval airbags. Airbags should be equipped with a heightening at the end.