Survival outcomes in low-level ejections from high performance aircraft.

Introduction: The modern ejection seat has evolved to a high standard of sophistication, significantly expanding the safe ejection envelope. Low-level ejections are at the margins of this envelope and the outcome depends on numerous factors, including aircraft attitude, airspeed, and vertical rate of descent. The purpose of this study was to analyze all published ejection injury studies, with particular emphasis on altitude at the time of ejection, to determine if low-level ejections have an overall higher fatality rate.

Methods: The aeromedical literature was reviewed for all studies relating to ejection outcomes in which the ejection altitude was recorded. Used in this analysis were 10 studies covering the period 1952-1997. Low-level ejections were defined as ejection below 500 ft (152 m) above ground level.

Results: There were 562 low-level ejections identified. Out of this number, there were 274 fatalities, giving a low-level ejection survival rate of 51.2%. There were 2607 ejections that occurred above 500 ft (152 m), with a survival rate of 91.4%. There was a significant difference between ejection survival rates below and above 500 ft (152 m). Low-level ejections have a significantly increased risk of a fatal outcome (Odds Ratio 10.07).

Conclusions: Ejecting from an aircraft below 500 ft (152 m) has a lower survival rate compared with the survival rate for all ejections. This is due to many factors, including the nature of the emergency, aircraft operating parameters at the time, and the inherent dangers of low-level operations. Low-level emergencies are time-critical events in which an early decision to eject can improve the chances of a successful outcome.