Objective To probe the causes of pilot's G-induced loss of consciousness (G-LOC) in air induced by push-pull maneuver (PPM) in human centrifuge training and instruct protective measures of push-pull effect (PPE) for pilots to promote the adaptation of PPE.Methods A pilot experienced air G-LOC induced by PPM participated in the basic tolerance determination and PPE training in human centrifuge.Relaxed + Gz tolerance was determined as qualification with 4.25 G sustained for 10 s.PPE protective training included:① 1 Gz/+4 Gz profile:from + 1.4 Gz baseline declined to-1 Gz with the rate of 1 G/s and sustained for 5 s,then climbed to +4 Gz with 2 G/s onset rate and sustained for 10 s.Pilot's suit pressure was 35 kPa.②-1 Gz/+ 5 Gz profile:from +1.4 Gz baseline declined to-1 Gz with the rate of 1 G/s and sustained for 5 s,and then climbed to +5 Gz with 2 G/s onset rate and sustained for 10 s.Pilot's suit pressure was 45 kPa.Relaxed +Gz tolerance,PPE tolerance of pilots and PPE protective effects were analyzed.Results Pilot's relaxed +Gz tolerance was qualified with the normal electrocardiogram and declined but not flattened ear opacity pulse amplitude.PPM protective measures training:①for-1Gz/+ 4Gz profile:pilot completed standard HP straining maneuver in the training.②for-1 Gz/+5 Gz profile:pilot didn't perform HP maneuver when acceleration transferred from-Gz to +Gz.Finally,he corrected to perform proper HP maneuver under the guidance of instructor and completed the training.Conclusions The improper PPE protective measure leads to the pilot's Gr-LOC in air but not the poor +Gz tolerance.Mechanism and protective measures of PPM and PPE should be preached and PPE protective measures training could be a part of human centrifuge training.

Objective To probe the causes of pilot's G-induced loss of consciousness (G-LOC) in air induced by push-pull maneuver (PPM) in human centrifuge training and instruct protective measures of push-pull effect (PPE) for pilots to promote the adaptation of PPE.Methods A pilot experienced air G-LOC induced by PPM participated in the basic tolerance determination and PPE training in human centrifuge.Relaxed + Gz tolerance was determined as qualification with 4.25 G sustained for 10 s.PPE protective training included:① 1 Gz/+4 Gz profile:from + 1.4 Gz baseline declined to-1 Gz with the rate of 1 G/s and sustained for 5 s,then climbed to +4 Gz with 2 G/s onset rate and sustained for 10 s.Pilot's suit pressure was 35 kPa.②-1 Gz/+ 5 Gz profile:from +1.4 Gz baseline declined to-1 Gz with the rate of 1 G/s and sustained for 5 s,and then climbed to +5 Gz with 2 G/s onset rate and sustained for 10 s.Pilot's suit pressure was 45 kPa.Relaxed +Gz tolerance,PPE tolerance of pilots and PPE protective effects were analyzed.Results Pilot's relaxed +Gz tolerance was qualified with the normal electrocardiogram and declined but not flattened ear opacity pulse amplitude.PPM protective measures training:①for-1Gz/+ 4Gz profile:pilot completed standard HP straining maneuver in the training.②for-1 Gz/+5 Gz profile:pilot didn't perform HP maneuver when acceleration transferred from-Gz to +Gz.Finally,he corrected to perform proper HP maneuver under the guidance of instructor and completed the training.Conclusions The improper PPE protective measure leads to the pilot's Gr-LOC in air but not the poor +Gz tolerance.Mechanism and protective measures of PPM and PPE should be preached and PPE protective measures training could be a part of human centrifuge training.