Aviation Fatigue Management - Case Study Example

Running Head: Aviation Fatigue Management Fatigue Management By _______________________ Abstract The fatigue has been a common word in the aviation field, there have been many problems in the early decades resulting in the massive losses of lives and machines, sooner the development took place such as the invention of various meters (Tachometer etc.) indicating the pilot the level of activities and suggesting the level at which the activities should happen, keeping the weather and surrounding conditions in view. For more safety, pilot’s physical fitness was also important, for enhancing pilot’s experience flight simulators were introduced which did a great job in managing the future possible fatigue and training the pilots to deal with it. Later, many new systems were installed in planes for pilot’s safety such as autopilot option, it was determined that there are merely seven factors that can affect the pilot’s performance during the flight, pilots these days are trained to cope with those factors so that no fatigue occurs at critical times. Introduction Stress and fatigue are words with a long history of use by scientist, practitioners, and the public. In both science and the workplace, these words are liberally and frequently employed, often with the assumption that they promote communication, concern, and change. Unfortunately, this is not always true. Research clearly indicates that both of these words refer to multidimensional and interacting constructs. Those who use stress and fatigue as references often fail to recognize this complexity and use these words in confusing ways. The role of human factors are always involved in the aviation. The purposes of aviation were principally adventure and discovery. To see an airplane fly was indeed unique; to actually fly an airplane was a daring feat. The early pioneers did not take it lightly, for to do so meant flirting with death in these fragile unstable craft. Thus, the earliest aviation was restricted to relatively straight and level flight and fairly level turns. The flights were performed under visual conditions in places carefully selected for elevation, clear surroundings, and certain breeze advantages to get the craft into the air sooner and land at the slowest possible ground speed. There were many problems with flights in the past decades due to poor system. Numerous accidents and several casualties were always caused due to the structural malfunction of just one basic component. Although human factors were not identified as a scientific discipline at this time, there were serious human factors problems in the early stages of flight. The protection of the pilot from the elements, as he sat out in his chair facing them head on, was merely a transfer of technology from bicycles and automobiles. The pilots wore goggles, topcoats, and gloves similar to those used when driving the automobiles of that period. Fatigue Management Attempts & Issues Colloquial use of the word fatigue by the populace is also common. For most of these users, fatigue refers to symptoms. In general, these symptoms are perceived to be the product of work or play, amid conditions that diminish performance. As a corollary, unlike many symptoms or diseases, fatigue is often assumed to be something that can be easily removed or reduced by rest. Thus, the nonscientist adopts what one might term a restitutional theory of fatigue. It is a theory that has evolved by intuitions and experience. The focus of science on what might be termed the fatigue problem is lengthy and varies with history. Many investigators have recognized that rest, like fatigue, is multidimensional. Rest does not always assure a full recovery of performance. However, restoration-by-rest continues to be an explicit or implicit part of the thoughts that many scholars have about fatigue. A manifestation of this is the fact that many investigators and theories of fatigue show a narrow and major interest in how long a person has been working at a task (time-on-task). These studies are perhaps best viewed as conscious or unconscious manifestations of the restitutional theory of fatigue. Dissatisfaction with the catchall concept of fatigue, as used by the general public, has certainly led to research aimed at obtaining a better understanding of this concept. However, the results of decades of fatigue research are sometimes confusing, often ignored, and certainly not easy to comprehend. For the most part, the scientific study of fatigue has not consolidated our thinking or solved many problems. The designers, manufacturers then thought about improving the machines. They were requiring the critical information regarding the system so that they could come up with a solution. Sooner the operators sensed the functions of the machine and they brought useful information to tackle the situation. “Soon these early craft had a piece of yarn or other string trailing from one of the struts of the airplane to provide yaw information as an aid in avoiding the turn-spin threat, and the Wright brothers came up with the incidence meter, a rudimentary angle of attack or flight path angle indicator” (Garland, Hopkins, Wise: 1999). As the increase took place in altitude capabilities and range of operational velocities, the human ability to accurately sense the vital differences did not increase. Therefore, the new devices had problems in detecting what their true operations were. As the change was not very sufficient, sooner the magnetic compass and barometric altimeter, pioneered by balloonists, were installed in planes. In addition, the unreliable engines were always causing problems for pilots and the plane manufacturers. “Either mechanical failure of the engine or propeller or interruption of the flow of fuel to the engine from contaminants or mechanical problems led to the introduction of the tachometer, to provide engine speed to the pilot, and of gauges about critical temperatures and pressures of the engine’s oil and coolant” (Garland, Hopkins, Wise: 1999). These were the first steps leading to fatigue management in the aviation field. The changes in the management were never enough as later it was found that most of the accidents take place because of the poor response from either the pilot or crew or both. Although the catch phrase ‘pilot error’ is all too often laid on the pilot who is guilty only of making a predictable response to ‘mistakes waiting to happen’ that are intrinsic to the design of his cockpit controls or displays or to the work environment surrounding him/her, there is no question that the greatest improvement in flight safety can be achieved by eliminating the adverse elements of the human component in the aircraft system. Although the most important contributor to aviation safety, the pilot is also the most complicated, variable, and least understood of the aviation ‘subsystems’. Pilot performance has been shown to be affected by everything from eating habits to emotional stress, both past and present. Scheduling decisions can disrupt the pilots’ sleep and rest cycles and impose the requirement for pilots to execute the most demanding phase of flight at the point of their maximum fatigue. Illness and medication can degrade performance markedly, as can the use of alcohol and tobacco. Although a complete exposition of all the factors that serve to determine or delimit pilot performance is all but impossible within the constraints of a single text, it is hoped that the following will at least sensitize the reader to many of the variables that have impact on the skill and ability of the commercial and general aviation pilot. The appearance of flight simulators not only has enhanced the training of aviators but has made possible a level of quantitative assessment of pilot performance that was not possible before the age of the simulator. The development of more and more sophisticated technology has made possible the level of realism enjoyed by today’s simulation efforts. The simulator came into its own in its support of the nation’s space program. Because there was no way that such activities as the docking of two space craft or a lunar landing could be practiced in real-world conditions, the simulator was the only way for the astronauts to develop the precise skills demanded by these mission elements. The appearance of computer automated acquisition and analysis of simulator-based pilot performance data has given rise to a new problem facing those who attempt to understand and interpret such findings. Automated performance measurement systems (APMS) are generally keyed to quantitative descriptions of aircraft state (e.g., altitude, airspeed, bank angle, etc.), which are usually plotted as a function of elapsed flight time. This time-referenced methodology can ignore the variable of pilot intention and can result in the averaging of performance inputs that may well have been made to accomplish totally different objectives but were grouped together solely because they occurred at the same temporal point in the task sequence. Some widely divergent measures of pilot performance in the course of simulations are found in the literature. It is not surprising that the measures used are generally dictated by the specific issues that the simulations are intended to study. In the joint Navy/ FAA study of penetration of severe turbulence by sweptwing transport aircraft, Hitchcock and Morway (1968) developed a statistical methodology allowing them to place probability values on the occurrence of given magnitudes of variation in airspeed, angle-of-attack, roll angle, altitude, and G-load as a function of aircraft weight, penetration altitude, storm severity, and the use of a penetration programmed flight director. This technique permitted the combination of several variables (e.g., G-loading, angle-of-attack variation, and airspeed deviation) into a multidimensional probability surface that described the statistical boundaries of the sampled population of simulated turbulence penetrations. At its Technical Center in Atlantic City, NJ, the FAA has conducted a series of man-in-the-loop simulations to determine the safety implications of proposed changes in the separation between parallel runways at several major airports. While the cockpit does inflict a stiff pressure, pilots usually remain fit and have enough stamina to survive without any problem. Whenever the word cockpit workload is used it usually refers to the combined mental and perceptual demands brought on by the flight pressure. Within the extensive literature describing the efforts performed to date in an attempt to determine the cognitive work loading imposed on a pilot during flight, according to Crabtree, Bateman, and Acton (1984) the preponderance of these studies were concerned with gaining insight into four principal issues: 1. Will the pilot’s current workload permit him or her to take on any additional tasks? 2. Is the pilot too overworked to properly handle an emergency should one arise? 3. Can the crew station and/or the piloting task be modified in such a way that the level of loading will be reduced? 4. Will a proposed new system reduce or add to the pilot's workload, either real or perceived? Most empirical workload assessment procedures produce dependent measures that can be subsumed under one of three general headings: (a) subjective assessments, (b) performance measures, or (c) physiological measures. Among the most popular techniques for the subjective assessment of work loading within the piloting environment are the Subjective Workload Assessment Technique or SWAT, the Subjective Workload Dominance Technique (SWORD), and NASA’s Task Load Index, the NASA-TLX. In an attempt to better define the elements of pilot workload, Hart and Staveland performed a study that assessed a number of separate measures of pilot workload (Garland, Hopkins, Wise: 1999), (a) a communications analysis, (b) subjective ratings of workload, (c) subjective ratings of other factors (stress, fatigue, mental effort, time pressure, and performance), and (d) heart rate and showed that generic workload was approximately the same for both pilot and copilot during seven flight segments encompassing all activities from preflight to landing rollout. When studied, the subjective rating of fatigue has shown a considerable boost across the flight duration, this factor was not found to correlate with the other measures of loading. The correlations connecting the subjective workload ratings and heart rate were significant for both pilot and copilot but were higher for the left seat. “It has been suggested that this difference reflects the fact that the responsibility for piloting the aircraft affected the pilot’s unconscious response to stress, because these correlations were more pronounced than were those between the purely subjective components” (Garland, Hopkins, Wise: 1999). By assuming a direct relationship between the complexity of the displays and controls associated with a driving task, Atsumi, Sigura, and Kimura (1993) also showed a relationship between what they classed as ‘mental work load’ and both heart rate variability and respiratory sinus arrhythmia. Within the aviation context, there are identifiable changes in voice pattern as a function of task-induced stress, although the direct relationship between these changes and workload is far more tenuous and rests only on the finding that speech ‘jitter’ shows a weak negative correlation with a measure of workload. Selcon, Taylor, and Koritsas (1991) had pilots use both the NASA-TLX workload scale and the Royal Air Force (RAF) Situational Awareness Rating Technique (SART) to rate videotapes of aircombat simulations. Although both techniques were sensitive to task difficulty, only the SART reflected difference in pilot experience. It has been found that the subjective workload ratings of memory demands increased as a positive correlate of age, whereas the ratings of psychophysical tasks showed no differences between age groups. Although intuitively satisfying and potentially useful in equipment design and flight procedure evaluations, these measurement methodologies and their findings, unfortunately, provide little new insight into the basic nature of nonphysical workload. At the very least, such findings as these indicate the need to be constantly alert to interactive uncertainties and limitations associated with the measurement of workload. The topic of pilot workload (and, indeed, of air traffic control [ATC] and maintenance personnel as well) is an extremely complex area and has been the subject of a significant number of book-length treatments on its own. The failure of aviation medicine to provide an objective, quantifiable, physiological definition of fatigue has allowed those investigating aircraft accidents and incidents to elect to disregard fatigue as a contributing factor in those cases where there is less than overwhelming evidence of its role as a cause. This reluctance can be defined as the traditional view of aviation engineers, an axiom as they saw it, that what cannot be measured with precision cannot be controlled. It can also be concurred that fatigue’s symptoms are manifested in so many different ways that, thus far, no precise definition of fatigue has been formulated and no very satisfactory method of studying it has been developed. On the other hand, it is also conceded that in the experience of every airline pilot, there are certain objective and subjective symptoms that he interprets as fatigue and that the operations manager often perceives as evidence of poor performance. The potential danger posed by fatigue is heightened by the fact that the very nature of the pilot’s task combines the opportunity for fatigue, arising from a sustained period of flight, with the maximum demand for piloting skill and alertness posed by a landing that is often made at night and frequently in bad weather. The pressures on aircrews to fly as long and as often as possible are the product of a number of factors intrinsic within the airline industry. As both the cost of aircraft and their rate of depreciation continue to grow, the need to maximize aircraft utilization time increases proportionately. The fact that current aircraft are so well designed that they can be flown for many hours with only a minimum of maintenance shifts the burden of being the limiting factor to the flight crew. The large number of different aircraft that many airlines now operate tends to limit the degree of interchangeability within their pilot pool. On those occasions when pilots do switch between aircraft types, it has been identified that the change in aircraft is often associated with an increase in both communication frequency and hand-flying, changes that carry a potential for increased fatigue. Further, in an attempt to reduce the costs by pilot reduction, the crew has faced more problems. “Indeed, the current trend to the use of two-person flight crews, as opposed to the three- and sometimes four-person crews of the past, has removed the option of carrying a ‘rested’ pilot along in the cockpit in case one were needed” (Garland, Hopkins, Wise: 1999). The need to balance schedule compliance with flight time regulations and crew preferences often leads to some degree of controversy. As early as 1949, the scheduled time for Pan American Airways (PAA) flight between Miami, Florida, and Belem, Brazil, exceeded the 8-hour flight time limitation. Establishing a relief crew layover in Port-of-Spain resulted in a need for the replaced crews to wait for more than a day for a return flight. The crews did not appreciate an extra day away from their home base and, because the total flight time for the route was just over 11 hours, the pilots, with the support of the Airline Pilots Association (ALPA), petitioned the Civil Aeronautics Board (CAB) for permission to exceed the 8-hr flight time limitation. The CAB ruled in their favor (Regulation Serial No. SR-345, May 10, 1950) thus transforming the flight time regulation from that of a mandate into the much more fuzzy realm of a negotiated agreement (Garland, Hopkins, Wise: 1999). Studies are currently underway to evaluate the feasibility and effectiveness of such fatigue countermeasures as in-cockpit naps, although such periods of in-flight rest are not currently sanctioned by federal regulation. In addition, the development of an expert scheduling system that incorporates the current physiological and pilot performance data has been proposed as an aid to commercial flight operations managers. Conclusion Many post accident investigations now include aviation human factors consultants and experts in addition to traditional accident reconstruction experts. 7 Aviation human factors forensics experts can serve to explain human behavior (right or wrong) with the equipment people use and often innocently depend upon. In most cases, the question is, why were the errors made? Could the errors have been avoided? Was the behavior typical, to be expected within the specific set of circumstances, or was it improper? Were there contributory factors involved such as fatigue, stress, intentional misuse, or even alcohol or drugs? Could the design be more error tolerant, and if so what are the trade-offs? Attorneys want an analysis of human and design-induced errors, both for their own understanding and to provide a credible approach to initiate or defend a lawsuit. Were errors the result of the individual or because of the design itself? Human errors might include attentional lapses, slowed reactions, inaccurate perceptions, risk-taking activities, and wrong expectancies stemming from inadequate situation awareness. Design induced errors might include problems induced by defective design, hidden hazards, inadequate protection or warnings, deficient instructions or training, or even improper integration with other systems. Juries expect more than a reconstruction of the events and an analysis of the crash dynamics. They want a reliable determination of the why (of behavior) along with the what (happened). Details about how the design was intended to be used and how it actually was used contribute salient evidence that often tilts the balance in their decisions. Reference Atsumi B., Sigura S., & Kimura K. ( 1993), “Evaluation of mental workload in vehicle driving by analysis of heart rate variability” (N.A). Crabtree,M.S., Bateman,R.P., Acton,W.H. (1984), “Benefits of using objective and subjective workload measures” (N.A.). Garland D.J., Hopkins V.D., Wise J.A. (1999), “Handbook of Aviation Human Factors”, Mahwah, NJ: Lawrence Erlbaum Associates. Hitchcock L. & Morway D.A. (1968), “A study of Swepting transport Aircraft”, (N.A.). Selcon S J, Taylor R M, Koritsas E. (1991), “The Human Factors and Ergonomics Society”, Santa Monica, CA. Read More