Abstract: An apparatus for maintaining useful consciousness and reducing the risk of injury for a subject exposed to high levels of acceleration with substantial components in the +G.sub.Z or -G.sub.Z direction while in a vehicle. It comprises a buoyancy force suit for supporting the subject with a buoyancy force, the force suit including at least two layers of flexible material, each layer being relatively impermeable to a substantially incompressible fluid having a specific gravity approximating blood being locatable in a space between the layers. A pressure helmet supports the subject's head with a gas pressure force. A Pressure Transfer System (PTS) provides pressure transfer and equalization between the suit and the pressure helmet. The PTS comprises a fluid reservoir segment and a gas reservoir segment. The fluid segment is in fluid communication with the space between the layers of the buoyancy force suit for maintaining a substantially constant fluid level within the suit at all times.

Abstract: A seat insert insertable within the existing seat of a vehicle for maintaining a crew member of the vehicle in a forward posture during high G acceleration. An elongated head support member is provided for supporting the crew member's head during a forward leaning posture. A back plate assembly including at least one back plate is connected to the head support member for supporting the spine in its natural curvature. Means being connected to the back plate assembly are provided for pivoting the back plate assembly forward relative to the seat of the vehicle. Means are provided for transfering any G-induced weight from the spine to the back plate assembly and ultimately to the existing seat of the vehicle. The head support member is restrained in such a manner so as to maintain the crew member's head in an "eyes up" attitude during a forward lean.