Anti-G Suit Protection and Body Position

Specifications for the anti-G valve dealing with outlet pressures to be furnished during sustained accelerations (Gz) relate only to the usual upright seated body position assumed by pilots flying conventionally configured aircraft. For modern high-performance fighter and attack aircraft, it has been proposed that the pilots be supinated in order to better tolerate the high G loads these aircraft are capable of generating. The study to be described was the second in a series conducted for the purpose of determining the effects upon relaxed G tolerance of some G protective techniques, including use of the AGS and supination. Six relaxed, G-trained subjects were exposed on the NAVAIRDEVCEN Dynamic Flight Simulator (DFS) to increasing G pulses in order to measure their G tolerance. Acceleration profiles consisted of haversine-shaped onsets and offsets lasting 2 or 8 s, with 15 s plateaus interposed. When the pressure delivered to anti-G suit (AGS) bladders was reduced in accordance with the calculated reduction in the height of the vertical hydrostatic blood column, brought about by supinating relaxed subjects, G protection provided by the AGS was greater than that provided when the relaxed subjects were seated upright.