Reduction of military high-altitude parachute entanglement using the controlled alternating parachute exit system.

The phenomenon of high-altitude parachute entanglement (HAE) results when two paratroopers have both a simultaneous and weak exit from the jump doors. They are then caught in the aircraft's slipstream and collision and entanglement follow. To avoid this phenomenon, the Controlled Alternating Parachute Exit System (CAPES) was introduced. CAPES focused upon manipulation of the exit technique to eliminate simultaneous paratrooper exit. Data from 90,894 consecutive parachute jumps revealed that the CAPES is highly successful in reducing te rate of high-altitude entanglement and the associated injury rate. CAPES seems to reduce the mid-altitude entanglement (MAE) and its injury rate but the results did not reach statistical significance as measured by chi square technique. The rate of landing or ground injuries, was essentially unchanged by the CAPES.