Early Flight and the Emergence of Human Factors Research

During the early years of 20th century aviation, it became apparent that the ability to maintaining human life and function at high altitude was only one of many human factors challenges associated with pow­ered flight. Aviation received its first big technological boost during the World War I years of 1914-1918.[303] Accompanying this advancement was a new set of human-related problems associated with flight.[304] As a result of the massive, nearly overnight wartime buildup, there were suddenly tens of thousands of newly trained pilots worldwide, flying on a daily basis in aircraft far more advanced than anyone had ever imagined pos­sible. In the latter stages of the war, aeronautical know-how had become so sophisticated that aircraft capabilities had surpassed that of their human operators. These Great War pilots, flying open-cockpit aircraft capable of altitudes occasionally exceeding 20,000 feet, began to routinely suffer from altitude sickness and frostbite.[305] They were also experiencing pressure-induced ear, sinus, and dental pain, as well as motion sickness and vertigo.[306] In addition, these early open-cockpit pilots endured the effects of ear-shattering noise, severe vibration, noxious engine fumes, extreme acceleration or gravitational g forces, and a constant hurricane – force wind blast to their faces.[307] And as if these physical challenges were not bad enough, these early pilots also suffered devastating injuries from crashes in aircraft unequipped with practically any basic safety features.[308] Less obvious, but still a very real human problem, these early high fly­ers were exhibiting an array of psychological problems, to which these stresses undoubtedly contributed.[309] Indeed, though proof of the human limitations in flying during this period was hardly needed, the British found early in the war that only 2 percent of aviation fatalities came at the hands of the enemy, while 90 percent were attributed to pilot defi­ciencies; the remainder came from structural and engine failure, and a variety of lesser causes.[310] By the end of World War I, it was painfully apparent to flight surgeons, psychologists, aircraft designers, and engi­neers that much additional work was needed to improve the human – machine interface associated with piloted flight.

Because of the many flight-related medical problems observed in air­men during the Great War, much of the human factors research accom­plished during the following two decades leading to the Second World War focused largely on the aeromedical aspects of flight. Flight surgeons, physiologists, engineers, and other professionals of this period devoted themselves to developing better life-support equipment and other pro­tective gear to improve safety and efficiency during flight operations. Great emphasis was also placed on improving pilot selection.[311]

Of particular note during the interwar period of the 1920s and 1930s were several piloted high-altitude balloon flights conducted to further investigate conditions in the upper part of the Earth’s atmosphere known as the stratosphere. Perhaps the most ambitious and fruitful of these was the 1935 joint U. S. Army Air Corps/National Geographic Society flight that lifted off from a South Dakota Black Hills natural geological depression known as the "Stratobowl.” The two Air Corps officers, riding in a sealed metal gondola—much like a future space capsule—with a virtual labora­tory full of scientific monitoring equipment, traveled to a record altitude of 72,395 feet.[312] Little did they know it at the time, but the data they col­lected while aloft would be put to good use decades later by human factors scientists in the piloted space program. This included information about cosmic rays, the distribution of ozone in the upper atmosphere, and the spectra and brightness of sun and sky, as well as the chemical composition, electrical conductivity, and living spore content of the air at that altitude.[313]

Although the U. S. Army Air Corps and Navy conducted the bulk of the human factors research during this interwar period of the 1920s and 1930s, another important contributor was the National Advisory Committee for Aeronautics (NACA). Established in 1915, the NACA was actively engaged in a variety of aeronautical research for more than 40 years. Starting only with a miniscule $5,000 budget and an ambitious mission to "direct and conduct research and experimentation in aero­nautics, with a view to their practical solution,”[314] the NACA became one of this country’s leading aeronautical research agencies and remained so up until its replacement in 1958 by the newly established space agency NASA. The work that the NACA accomplished during this era in design engineering and life-support systems, in cooperation with the U. S. mil­itary and other agencies and institutions, contributed greatly to infor­mation and technology that would become vital to the piloted space program, still decades—and another World War—in the future.[315]