Abstract : The purpose of the reported effort was twofold: to develop rotary- wing landing gear concepts and criteria which, when applied, would lessen the magnitude of crash forces transferred to occupiable areas of helicopters involved in severe yet survivable accidents; to use the concepts and criteria to design, fabricate, and test an experimental prototype skid landing gear system. Landing gear design criteria, crash criteria, energy-absorbing design criteria, and applicable specifications were collected and analyzed to establish the state of the art in the landing gear design and energy absorber design. Once this was accomplished, the data were used to develop preliminary design criteria and concepts for three classes of rotary-wing aircraft. The concepts were selected to be compatible with combined loads and various attitudes.