Human Physiological Responses to Push-Pull Acceleration as Experienced in Helicopters

摘要

NAWCAD Patuxent River assessed the risk to helicopter aircrew of acceleration stress by investigating the human physiologic response to transitions from -1 Gz (push) to +4.5 Gz (pull) loads. Nine volunteers participated in a human centrifuge study in which nine actual helicopter maneuvers were reproduced in a 1 hr mission scenario (push-pull mission (PPM)) which simulated both current (current mode (CM): -0.2 to +3.5 Gz) and future capabilities of U.S. Navy helicopters (future mode (FM): -1 to +4.5 Gz). Additional scenarios were run in which transitions < 1 Gz were fixed at +1 Gz. Blood pressure, loss of vision, and subjective fatigue were measured. Visual decrements were trivial during CM while muscular tensing was required to avoid blackout during FM. Subjects tolerated the range of Gz-stresses associated with current U.S. Navy platforms. When subjected to FM PPM G-loads (typical of current U.S. Army platforms), cardiovascular stress significantly increased, Gz tolerance dropped up to 1.2 g, and heart rate increased as much as 67 bpm. Four subjects reported Almost-loss of Consciousness symptoms during FM. While G- stress experienced by aircrew generated by current helicopters does not appear to present a high risk, G awareness training is recommended to reduce risks to aircrew exposed to G-loads generated by more aggressive helicopters.