The motion of occupants seated in a typical side facing seat in a general transport aircraft was analyzed using the DYNAMAN simulation program. This paper presents the results of the first phase of the study, where simulations were performed to validate the computer model against a set of tests performed at CAMI using Hybrid II and Hybrid III dummies. There was usually good agreement between test and simulation of the pelvic and chest accelerations, and right side lap belt and shoulder belt loads. The head accelerations tended to be underestimated and the neck and pelvic loads and moments overestimated in the simulations. The only injury parameter which consistently exceeded the tolerance value was the lateral moment at the head-neck junction.