For this analysis, the lift force is assumed to be zero. The equations of motion are solved numerically and the trajectories are calculated for the aircraft and jumper. The technical details are beyond the scope of Sport Parachutist's Safety Journal , but may be made available to interested persons. The separation distance between a jumper's center of gravity and the leading edge of the horizontal stabilizer, as shown in Fig. 1, is the determining criteria as to whether or not contact between a jumper and the aircraft is possible.
Safe exits occur when the separation distance is sufficiently large.
Unsafe exits occur when the separation distance becomes too small. The separation distance is calculated from the trajectories of the aircraft and jumper at each instant of time. A scenario must be mathematically described to model the initial positions and velocities of the aircraft and jumper. Several cases are studied and listed below, along with plots of the separation distance as a function of time. In all cases the aircraft's attitude is assumed to be level.