A correlative investigation of simulated occupant motion and accident report in a helicopter crash.

BACKGROUND In the late 1980's, an Army Apache helicopter crashed during a training mission, resulting in fatal injuries to the rear seat pilot and survivable injuries to the front seat copilot. U.S. Army investigators assessed the aircraft damage and aircrew injuries, and examined the helmets, restraint systems, and crashworthy seats. HYPOTHESIS Computer simulations that approximate an actual crash event can provide insightful output (human body motions and forces on the human body) that illuminates our understanding of the injury dynamics and the effect of safety systems designed to minimize injury. METHODS Crash kinematics and vehicle accelerations were derived from the investigation and inferred from the aircraft damage, and input to a computer-based analytical simulation that calculated the dynamics and forces to which the crew were exposed. RESULTS We treat the simulation like a looking glass into the event, revealing how and when safety devices could have responded during the crash, and the nature of injury-producing forces experienced by the occupants. Computer simulated whole-body and head-neck motion are graphically displayed, along with plots of joint forces, seat stroke, harness belt acceleration, and occupant accelerations. CONCLUSIONS The calculated motions and forces indicated that injuries found in the accident were likely, hence the simulation may indeed be representative of the actual event.