PROBLEMS RELATING TO AIRCREWS IN AIR TRANSPORT DESIGN

The future success of civil air transportation will depend primarily on two factors, namely, safety and regularity. In regard to safety, there has lieen a sharp decline in passenger fatality rates over the past 20 years, and the improvement has taken place while the amount of traffic has been increasing a t an extremely rapid rate. Further increases seem likely, but the industry is greatly concerned over the effect that a major accident has on the traveling public. Fear and unreliability of operations play a major role in discouraging newcomers as well as experienced travelers. Althoiigh the regularity of services has also been improving, much remains to be accomplished before a perfect safety record can be attained along with 100 per cent regularity. Many capable experts disagree as to the methods of improving safety. Some believe that the answer is to eliminate the human factor by means of flight control systems which are completely automatic. Others believe that the modern transport should be so mechanically simplificd and perfected that it can be manually controlled with ease. Regardless of the method which eventually succeeds, there remains an immediate necessity for studying the human problems relating to the aircrews if marked improvements are to be expected witliin the next few years. Naturally, the pressure to obtain greater safety and regularity creates certain problems for the aircrews. It is the purpoçe of th is paper to select a number of illustrations of current interest and importance which relate aircrew duties to design features. Since most errors are attributed to human factors, or so-called “pilot error,” it seems only logical to analyze what is expected of airmen in relatiori to the equipment which they must fly. The greatest chances for improveinent of safety, efíiciericy, and regularity depend on improvements in the design and operation of equipment in terms of human limitations and capabilities. Many illustrations can bc given of the way in which modern technology has produced machines without adequate concern for the capacities of thc operators, and modern air transports offer no exceptions. If aviation is to make significant progress in the immediate future, I feel very strongly indeed that mechanical design must be more intimately related to the physiological and psychological characteristics of the operators. Aircraft must be built around the aircrews rather than fitiirig them in without due regard for their human characteristics, an occurrence which has liappened so frequently iii the past Before showing the importance of this fact in aviation, two illustrations will l e drawn froni the modern range finder and military tanks. Witli regard to range finders, our studies showed that the instruments were very accurate and that the human eye was capable of great precision in making visual judgmeiits.l When the subjects were looking into the range finders, however, the errors were very great. The range finders had to be re-