a
reference to either of two
points where a person starts to
lose his vision and
consciousness due to forces exerted on his
body during
flight, specifically called
red out and
blackout. A
red out occurs when a pilot is accelerating in his
craft and blood is forced into the head, as during a rapid vertical climb. This can result in the pilot's vision turning
red (from a pooling of blood behind the eye) and possible
unconsciousness. A
blackout occurs when blood is forced out of the head and to the lower parts of the
body, as when a high-speed
turn is made. This can result in fading vision or
temporary blindness, and possible
unconsciousness.