, 1999, p. 315). This point is also made by Doyle (2002), who reports that, "In fact, airline companies take pilot fatigue very seriously because they also have to contend with jet-lagged pilots" (p. 128). Indeed, the introduction of these sophisticated aircraft, replete with a vast array of displays and controls, can in and of itself result in increased pilot fatigue. According to Mouloua and Parasuraman (1996), "Increasing task demands, such as increasing the number of displays that the pilot must monitor, also increases workload, particularly during demanding flight segments. Pilot fatigue also increases workload because it can reduce the capacity of the pilot to respond to task demands in a timely or appropriate manner" (p. 120). The authors provide a useful schematic to help illustrate how these processes play out in real-world settings by introducing the factors of pilot skill, feedback and system reliability and how these factors can affect the level of pilot fatigue experienced in a given situation, as shown in Figure 1 below.

Figure 1. Factors that influence pilot workload.

Source: Mouloua and Parasuraman, 1996, p. 119.

In addition, Mouloua and Parsuraman point out that ergonomic design factors in how the cockpit is arranged can reduce or contribute to the level of pilot fatigue: "Other relationships between these human factors issues and workload-shaping factors can occur. For example, allocation of function decisions can have an effect on system reliability; controls with poor stimulus-response compatibility can increase pilot fatigue levels" (1996, p. 134). Cockpit design issues are also described by Backs and Boucsein (2000) as being potential sources of pilot fatigue, and note that pilots may experience increased muscle tension (especially in the neck muscles) from highly computerized cockpit configurations and even the types of lights used in the display and throughout the cockpit can both contribute to the level of pilot fatigue. On a final note, some other factors that may play a role in contributing to the incidence of pilot fatigue include flight scheduling, responsibility and decision making, the nature and stability of marital relationships, pilots' lack of social...

Further, it would seem that whenever technological innovations are introduced to solve one type of pilot fatigue problem, they tend to introduce still others that may be unexpected and certainly unintended. Because pilots are just people, they are subject to the same types of emotional and physical ills that everyone else is too, but their level of responsibility for the lives of others makes these issues more severe and the need for better oversight is abundantly clear. Unfortunately, the research also showed that in an increasingly competitive marketplace, pilots will likely continue to be subjected to the same types of conditions that have been shown time and again to produce pilot fatigue, including longer flight hours and less time between flights in which to rest. In the final analysis, until the day comes when aircraft are completely autonomous and do not require human control, the issue of pilot fatigue will remain relevant and important to the flying public, pilots and policymakers alike.