Guidelines for a research and development (R&D) program for high sustained G.

This article is a contribution to the workshop on "Operational Requirements in the Prevention of G-Induced Loss of Consciousness (G-LOC) in High Performance Aircraft"; it focuses on the "operational" side of the requirements to prevent G-LOC. There are two types of requirements for prevention of G-LOC; a) pre-G-LOC detection devices that monitor physiologic changes of the pilot before G-LOC occurs, and b) the more generic personal G protection systems that increase G tolerance. Recently there have been major advances in G-protection research and development (R&D) systems (soon to become operational) that significantly improve G-level and G-duration tolerances. We do not know the extent of the impact of these new systems on G-LOC, but it could be substantial. These near-term operational anti-G systems are: 1. Positive pressure breathing (PPB) systems assisted by chest counterpressure that are activated by an increase in G levels; i.e., the higher G level, the greater the pressures applied to the aircrew member (Morgan et al., 1992). This PPB system is known as PBG. PBG has been flight tested with the standard operational anti-G suit. This test program known as Combat Edge significantly reduces pilot fatigue and extends G-duration tolerance. In limited operational testing of F-16 and F-15 aircraft, PBG has received substantial pilot acceptance. 2. An improved anti-G suit that provides uniform pressure of the lower body that includes the operational anti-G suit abdominal bladder. This new anti-G suit concept increases both G-level and G-duration tolerances (Krutz et al., 1990; Morgan et al., 1992). Flight tested as the Advanced Tactical Anti-G Suit (ATAGS), it is comfortable and preferred by pilots over the standard operational anti-G suit. 3. The combination of Combat Edge and ATAGS, the most advanced anti-G system in the final stages of development (Morgan et al., 1992). This anti-G equipment has been tested in the laboratory on the centrifuge. Experimental subjects are able to tolerate 8 to 9G "relaxed" or with a minimal anti-G straining maneuver (AGSM) (Morgan, 1992). Accleration scientists believe that once these systems become operational on high performance aircraft that the incidence of G-LOC will be significantly reduced, particularly G-LOC associated with fatigue.