September 1999

Air traffic controller performance (Air Force Research Laboratory, Wright-Patterson AFB, OH): “This paper provides a brief historical overview of air traffic controller (ATC) selection, reviews current U.S. Air Force (USAF) selection procedures for enlisted ATC trainees, and summarizes the results of three recent studies … Study 1 examined the validity of the operational selection test (i.e., Armed Services Vocational Aptitude Battery or ASVAB) against apprentice-level training performance. Study 2 evaluated the impact of alternative selection procedures on training attrition and eligibility for training. Study 3 reviewed the results of a survey of enlisted ATCs designed to identify the personnel characteristics and organizational factors that influence training and job performance … The current selection composite demonstrated acceptable validity for predicting apprentice-level training performance. Alternative cut-score analyses revealed that raising the minimum qualifying score in order to reduce attrition by 5% would lead to an unacceptable 20% reduction in the number of eligible ATC candidates. Using a different ASVAB composite for selection would have less overall impact on the qualification rate, but would disproportionally disqualify women. Results of a survey of enlisted ATCs indicated they were generally satisfied and motivated. In addition, they identified several abilities required for on-the-job performance that are not measured by current USAF selection methods. These included memorization and retention of new information, spatial orientation/visualization, ability to work well in stressful environments, ability to shift between two or more sources of information, and ability to combine and organize information.” ¹

September 1974

Aircrew fatigue and recovery (Environmental Physiology Branch, USAF School of Aerospace Medicine, Brooks AFB, TX, and Aeromedical Services, USAF Dispensary, Pease AFB, NH): “Fifteen biomedically dedicated missions of 8 h duration were flown in the FB-111 as part of its initial operational evaluation. Each two-man crew provided data on subjective fatigue, discomfort, efficiency, and pre- and post-mission sleep. In addition, urine samples obtained from one crew on an unusually demanding mission were analyzed for epinephrine, norepinephrine, 17-hydroxycorticosteroids, sodium, potassium, and urea. The data showed that the crews experienced moderate fatigue and stress, aggravated by physical discomfort, from which they recovered after one night of sleep.” ²

September 1949

Reaction time in radial acceleration (University of Southern California, Los Angeles): “The changes in [reaction time] with increased positive radial acceleration are well beyond the 1 per cent level of significance. Such factors as fatigue, warmup, anticipation, habituation, and the like appear to have been adequately controlled. Increased radial acceleration seems to produce a definitely slower reaction time where the time required to complete the reaction movement itself is negligible, as it was in this study. The increase in time can be attributed to either a reduced sensory efficiency, a decreased efficiency of the central nervous system, or a combination of the two …

“In view of the fact that reaction time to auditory cues is apparently faster than that to visual cues, it seems reasonable to suggest that crucial signals to the aircraft pilot might better be given by sound than with red lights. Further, since the loss of vision, presumably due to the intraocular pressure of the eye, occurs prior to unconsciousness, while the hearing faculty is still present, auditory cues provide a means to signal the pilot when he would be unable to react to visual cues …

“It is concluded on the basis of the experiment reported here that the reaction time to both light and sound stimuli becomes significantly longer under conditions of increased radial acceleration. The superiority of reaction to sound, in addition to the known failure of sight at crucial g-levels, suggests the advisability of presenting important signals to the pilot in the auditory sense modality rather than the visual. This is especially vital in those cases where such signals demand emergency action. The tremendous speed of the aircraft of today and tomorrow will necessitate action to conserve every split second. Taking steps such as those suggested here should help to take some of the burden from the limiting factor in aircraft design – the pilot.” ³