The G-excess effect

Spatial disorientation (SD) is a major cause of aircraft mishaps in military as well as civilian aviation. Despite steady improvements in flight safety, SD-related losses remain unacceptably high and warrant special attention. SD occurring at low altitude is a particular problem, as there is little time for the pilot to recognize the problem and to take corrective action. Inevitably, under such circumstances, mishaps are common and aircrew rarely survive. To illustrate the problem faced by aircrew in overcoming disorienting illusions, this article looks at one possible cause for SD in the low-level environment-the G-excess effect-and describes a recent Royal Air Force mishap in which this illusion may have played a part.