ONE OF the consequences of flying at high velocities is that changes in direction or speed may produce profound physiological effects in the pilot. These accelerative forces are known as g forces (expressed as multiples of the gravitational attractive force). Depending upon how the force is vectored through the body of the subject, it is referred to as a positive, negative, or transverse g force. Military maneuvers, such as gunnery and dive bomb runs and steep inside turns, produce a characteristic group of symptoms culminating in black-out and unconsciousness which are known collectively as the physiological effects of positive g.*
Many authors use the words "black-out" and "unconsciousness" interchangeably. In an effort to counteract this semantic error, the term amaurosis fugax has been substituted as a more accurate and all-inclusive description.† However, this is not fully warranted, because clinically amaurosis fugax refers to a temporary loss of vision, such as