Ross A. McFarland

Analysis of the electrocardiograms obtained from 1000 young healthy aviators

Abstract During the course of some investigation 1 on a group of Civil Air Line pilots, the electrocardiographic findings proved to be of more than passing interest because of the relatively large number of deviations from the values generally regarded as being normal. Because of their relatively frequent occurrence in the records from apparently healthy persons, it was not easy to believe that all of these deviations declared some underlying cardiac abnormality. The opportunity to extend this study came a year later when electrocardiograms were obtained from a large number of young aviators at the Naval Air Station, Pensacola, Florida. Although the primary purpose of this study is to add to our knowledge of the range of the normal electrocardiogram, some attention is also given to an appraisal of the usefulness of electrocardiography in aviation medicine.

Understanding Fatigue in Modern Life

Abstract Since fatigue in its many forms can result from a variety of causes acting singly or in combination, it is difficult to give clear-cut rules or principles for its control or prevention. Each case must be evaluated according to its own peculiar characteristics. For the individual suffering from chronic fatigue, the most logical first step would be an examination by a physician to determine whether or not any organic basis for the condition exists. Where it does not, attention must be directed towards finding the most likely cause, and making the necessary changes in ones life and schedule of living. A few recommendations of general applicability would include: adequate sleep; the establishment of a daily work-rest cycle acceptable to the individual; the elimination of conditions resulting in excessive stress, anxiety, or boredom; the institution of a definite, adhered-to schedule of physical exorcise or sports; the possible use of stimulants or medications. For the organizational control of fatig...

HUMAN FACTORS IN HIGHWAY-TRANSPORT SAFETY

ACCIDENTS ARE ANALYZED FROM THE STANDPOINT OF HUMAN FACTORS AND ACCIDENT PRONENESS. MANY VARIABLES ARE RECOGNIZED THAT CONTRIBUTE TO MOTOR TRANSPORT ACCIDENTS. IMPROVEMENT CAN BE ACCOMPLISHED THROUGH INCREASED VIGILANCE AND RESEARCH WITH REGARD TO THE DESIGN OF EQUIPMENT, THE SELECTION AND TRAINING OF PERSONNEL AND SAFE OPERATING PRACTICES. IT IS CONCLUDED THAT THE PREVENTION OF ACCIDENTS REQUIRES TEAMWORK OF (1) RESEARCH SPECIALISTS, (2) OPERATORS WHO ARE CONCERNED WITH ROUTINE SCHEDULING AND MAINTENANCE OF EQUIPMENT, AND (3) THE MANAGEMENT GROUPS INTERESTED IN MAKING AN OPERATING PROFIT.

LOW LEVEL EXPOSURE TO CARBON MONOXIDE AND DRIVING PERFORMANCE

Subjects were exposed to low levels (700 ppm) of carbon monoxide (CO) until carboxyhemoglobin (COHb) levels of 6%, 11%, and 17% were reached, and they were then tested as to their ability to perform both selected driving-related laboratory tests of visual response and control reactions and over-the-road vehicle driving. These test results were then compared with those on the same subjects taken under control conditions without exposure to CO. The overall pattern of results indicates that a 6% COHb level had no effect on driving ability, and that COHb levels of 11 % and 17% did not appear to seriously affect the ability to drive motor vehicles, as measured by the tests administered in this study. However, certain statistically significant differences were found in some of the tests that suggest some decrement in performance as a result of CO exposure.

Accident epidemiology and the design of the residential environment

By its design, the housing which should be built in vast quantities in the near future can prevent accidents, minimize injury, and facilitate rehabilitation, both directly and indirectly. Studies are described which have examined relationships between housing and accident rates in general, and in particular, fires, pedestrian accidents, and accidental poisoning. Better design should reduce the harmful effects from these sources and from falls. Preventive measures have been or can be taken also against minor-accident epidemics involving glass doors, oil stoves, poisonous plants, and rat bites. There are many ways to make our residential environments safer.

A CRITIQUE OF ACCIDENT RESEARCH

The gains made in the control of accidents over the past t h t y years appear on the whole to be relatively small as compared to the improvement in the control of disease. Also, the overall population death rates from accidents have decreased only slightly. Indeed, in some important classes of accidents, such as those involving motor vehicles, one can scarcely say that an individual’s chances of avoiding being fatally injured in a given year have really been improved at all (Terry, 1961; McFarland and Moore, 1962). Comparisons concerning nonfatal injury are less reliable, but the findings in the recent National Health Survey indicate that a formidable problem remains to be solved if effective control of accidents is to be achieved. Each year in the U. S. about 47 million persons suffer nonfatal injury, severe enough to require medical attention, or to result in a curtailment of usual activity for a day or more (Terry, 1961).

Threshold and Rate of Dark Adaptation as Functions of Aǵe and Time

In order to describe one family of dark adaptation curves obtained from an age sample ranging from 16 through 89 years, a mathematical model of the form was derived. It was found that the model could be generalized. In addition it was concluded that threshold of dark adaptation as a function of time was lawfully related to chronological age. Rate of adaptation was determined by differentiating the equation at time 30 sec and time 6 min as follows: The results showed that rate of dark adaptation was a curvilinear function of age. These findings are consistent with the hypotheses that dark adaptation threshold and rate of dark adaptation depend upon basic underlying physiological processes that change with age.

HUMAN LIMITATIONS AND VEHICLE DESIGN

This paper contains a review of research on road vehicle design in relation to human physiological, anthropometric and psychological factors

Ergonomics around the world-The United States of America.

The history and development of human factors engineering, or ergonomics, and of the Human Factors Society, is traced for the American scene. Selected problems of current interest are given from the fields of aviation, highway safety, architectural design, environmental control, and consumer products. In conclusion, the more significant areas which might occupy specialists in this field during the next decade are emphasized.

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-