Oxygen and acceleration

Significant numbers of high performance fighter aircraft continue to be lost due to acceleration (Gz)-induced loss of consciousness. This is due to the rapid onset of high sustained Gz which results in the sudden loss of blood flow to the brain. Present research efforts to extend Gz tolerance are directed toward the maintenance of cerebral blood flow, i.e. straining maneuvers, anti-G suits, tilt seats. The purpose of this paper is to review the present situation and discuss the potential benefit of breathing 100% oxygen at high pressure. Basic science evidence and experience with hyperbaric oxygen in the clinical setting suggest that if the oxygen concentration in the brain tissue is increased, prior to the onset of Gz, additional time of useful consciousness may be realized. The advanced tactical fighter, now in the design stage, will have a sustained Gz capability of 12-14 Gz. This is above human tolerance at the present time and provides an impetus for future acceleration research. Continued aircraft loss due to Gz loss of consciousness will remain an operational problem in aerospace pathology in the 1990s and beyond.