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Updated: May 27, 2026

A Modeling and Simulation Method for Preliminary Design of an Electro-Variable Displacement Pump
Published on: June 1, 2022
A centrifuge simulated push-pull manoeuvre with subsequent reduced +Gz tolerance
Yan Xu1, Bao-Hui Li, Li-Hui Zhang
1Department of Aerospace Biodynamics, Faculty of Aerospace Medicine, Fourth Military Medical University, Xi'an, People's Republic of China.
Abstract:
The push-pull effect (PPE) has been recognized as a deleterious contributor to fatal flight accidents. The purpose of the study was to establish a push-pull manoeuvre (PPM) simulation with a tri-axes centrifuge, studying the effect of this PPM on the +Gz tolerance, and to make this simulation suitable for pilot centrifuge training. The PPM was realized through pre-programmed acceleration profiles consisting of -1 Gz for 5 s followed by a +Gz plateau for 10 s. Relaxed +Gz tolerance recordings were obtained from 20 healthy male fighter aircraft pilots and 6 healthy male volunteers through exposure to pre-programmed profiles with and without previous -1 Gz exposure. A statistically significant decrease in +Gz tolerance was seen in all subjects after -1 Gz for 5 s exposure, 0.87 ± 0.13 G in the volunteer group and 0.95 ± 0.25 G in the pilot group. The ear opacity pulse as a +Gz tolerance endpoint criterion was sometimes found to be unreliable during the PPM experiments. The simulated PPM in this study elicited a PPE, which was obvious from the significant reduction in +Gz tolerance. The PPM profile appears useful to be included in centrifuge training.
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