Aviation medicine is a branch of medicine that applies medical knowledge to the human factors in aviation. Every factor contributing to a safe flight has a failure rate. The crew of an aircraft is no different. Aviation medicine aims to keep this rate in the humans involved equal to or below a specified risk level. This standard of risk is also applied to airframe, avionics and systems associated with flights.
Medical examinations aim at determining any elevation in risk, such as a tendency towards myocardial infarction (heart attacks) or the presence of diabetes, etc.
Other screened conditions such as colour blindness can prevent a person from flying because of an inability to perform a function that is necessary. In this case to tell green from red.
Passive vs. Active Failures
Anything in the system can fail in two ways. Passive failures occur when something stops working. Examples would be an artificial horizon stops working and a flag shows that it has failed or a pilot who loses consciousness. Active failures occur when the item continues to function but in an incorrect manner. Examples would be a trim motor which kept going after the switch was released or a pilot who develops psychotic thinking and behaves in response to that.
Aerospacemedicine is a subdiscipline of preventive and emergency medicine that ties together physics, life support, and medicine to protect aircrew and patients in the realm of aerospace.
Aerospacemedicine is seldom included in emergency medicine training curricula, but most ED physicians will encounter problems related to the flight environment.
Medicine is a constantly changing science and not all therapies are clearly established.
It has two sub-branches: aviationmedicine, concerned with flight in Earth's atmosphere and under at least normal Earth gravity, and space medicine, concerned with flight beyond the atmosphere in which humans are typically exposed to a fraction of normal Earth gravity.
Aerospacemedicine has its roots in the 18th-century physiological studies of balloonists, some of whom were physicians.
Aviationmedicine was recognized as a specialty of preventive medicine by the American Medical Association in 1953 and saw its name change to aerospacemedicine in 1963.