The number of flight surgeons authorized in Vietnam reached a maximum of 86 in August 1968; by November, 98 were actually assigned there. This maximum contrasted with shortages during such periods as August 1967, when these assignments fell to 40 percent below the authorized strength.

The flight surgeon, assigned to a unit of an aviation brigade, was supported by a medical detachment team which provided dispensary service. These teams were assigned generally on a basis of one detachment per two aviation companies. The unit flight dispensary was usually located next to the airfield, often in a unit billeting area, and the flight surgeon and his staff usually lived with the troops that they served. This arrangement, allowing for optimum rapport and medical services, was especially advantageous when the airfields were, under attack, and it proved vital during the 1968 Tet Offensive, when many airfields, were isolated.

Flyer Fatigue

The aeromedical problems that faced Army aviation, units in Vietnam provided a challenge to their supporting flight surgeons. No problem, however, was more common yet more elusive than that of flyer fatigue. It became more pronounced after 1965 when the buildup of U.S. forces gained momentum and remained a significant limiting factor in the conduct of airmobile operations. By the end of 1966, aviators were flying 100 to 150 hours or more per month, and the need to know how much an aviator could fly before, he was so fatigued that he was no longer effective or safe was evident.

Army aviators were assailed by a multitude of stresses, each to some extent capable of endangering their missions. The stress from hostile fire was aggravated by such factors as heat, dehydration, noise, vibration, blowing dust, hazardous weather, exhaust from engines and weapons, and labyrinthine stimulation. Additional stress was caused by psychic elements, such as fear, insufficient sleep, family separation, and frustration. These stresses, acting on the aviator day after day, combined with the physical exertion of long hours of piloting an aircraft, caused fatigue.

The ever-increasing requirements during the years 1967-68 for aviation support caused the accrual of extremely high aviator flying times in all units. Night operations, with their extra demand upon the critical judgment of the aviator increased. The shortage of crews often forced an individual to undertake both day and night missions without adequate rest.

In response to expressed concern of the unit commanders and of aviation safety officers, flight surgeons at all levels of aerornedical support studied every aspect of the fatigue problem. Because fatigue was the result of many variables, it defied easy definition and precise measurement.