Many documented incidents can be linked to pilot fatigue. A case in kind occurred on August 18, 1993, where a Connie Kalitta DC-8 crashed whilst completing its 1/4-mile base leg. The flight crew had flown for 9 hours and been on duty for 18 hours, accordingly disrupting their circadian rhythm and experiencing sleep loss (National Transportation Safety Board, 1993).
Showing how fatigue was determined to be a contributing safety factor in the event
That the accident was, to a great extent, contributory to sleep loss was confirmed by Jim Danaher, chief of the NTSB's Operational Factors Division at the November 1995 Fatigue Symposium near Washington, D.C.:
The company had intended for the crew to ferry the airplane back to Atlanta after the airplane was offloaded in Guantanamo Bay. This would have resulted in a total duty time of 24 hours and 12 hours of flight time…."(National Transportation Safety Board, 1993).
The NTSB accident report also noted the cause of the accident as likely attributable to "The impaired judgment, decision-making, and flying abilities of the captain and flight crew due to the affects of fatigue" (ibid).
The report proceeds to list other causes, but fatigue is indicated as the primary factor. This, notes Brandon Printup (2000), is rare since fatigue is usually listed as an 'additional cause' with some other factor presented as primary contribution. Here, lack of sleep assumes foremost position whilst the Additional Factors section, in this instance, only displayed criticism on the FAA for inadequate flight and duty time regulations which factors, incidentally, conspired to produce existence of fatigue.
III. How contemporary fatigue science supports my argument that the significant causal factors of the event were fatigue impairment of the flight crew
Scientific research on sleep presents something of a paradox since, whilst on the one hand, it indicates that sleep deprivation is a condition that can be rectified and relatively insignificant, on the other hand, evidence seems to indicate that sleep deprivation may cause major, even fatal, harm. It is for this reason that sleep deprivation is not taken seriously enough, but, in reality, the extent of the harm caused by sleep deprivation depends on a variety of factors including the amount of sleep lost and on other aspects of the individual's circumstances, environment, and life (Weiten, 184). Negative effects of lack of sleep are most likely to occur when the individual has to deal with stress in his or her job or personal situation, when this stress is long lasting, or when individuals are faced with long-lasting, monotonous tasks. Negative effects of sleep deprivation are also likely to occur when individuals restrict their sleep to 6 hours or less for repetitive nights in a row (Weiten, 184). Then again, some individuals are more sensitive to sleep restriction than are others. Approximately, 20% of adults are routinely sleep deprived (Dumer & Dinges, 2005).
a. Neurobiology of the sleep-wake regulation cycle
The negative effects of sleep deprivation are due to the fact that the neurobiology of the regular sleep-wake regulation cycle is disrupted. There are four stage of sleep with the first called REM (rapid eye movement) where the mind is still partially active. This is succeeded by the next three stages where sleep as we know it occurs, and then again a brief interlude of REM during which stage dreams occur. This cycle occurs various times during the night, and the whole is moderated and modulated by a biological clock (otherwise known as circadian rhyme or changes) that is located in the suprachiasmatic nuclei that is in the hypothalamus. The biological clock does not only deal with sleepiness but affects all neurobehavioral variables with its circadian rhythm. This includes cognitive performance. What this means is that on a regular sleep-wake pattern, an individual can usually think (therefore function) in a consistently coherent, stable manner. Deprivation of sleep interrupts this circadian rhythm and may elevate homeostatic pressure of this clock to the extent that waking neurocognitive functions are weakened so that they function poorly even during the period of peak circadian wakefulness (Dumer & Dinges, 119). Pilots, for instance, may be especially vulnerable to this condition since they experience long schedules and predictable changes in circadian rhythm.
b. Psycho-Biological effects of sleep-deprivation
It is for this reason that sleep deprivation is more injurious than is generally believed, and fatigue science shows that sleep restriction impacts the brain in a similar manner to that of alcohol consumption. Prolonged lack of sleep can produce psychomotor impairments such as impeding individual's attention, corrupt his reaction time, impair his motor coordination, and weaken his decision making. It may also negatively impact his or her endocrine and immune system functioning (Weiten, 185). In fact, a study of professional truck drivers found that after 28 hours lack of sleep, drivers evidenced cognitive deficits similar to those found after alcohol intoxication (BAC at 0.1%) (Dumer & Dinges, 118).
That neurocognitive impairments occur due to lack of sleep is a fact that has long been validated. The most classical study was in 1896 on three adults who experienced 90 hours of continuous wakefulness (Dumer & Dinges, 125). Since that time, numerous studies have documented the negative impact of sleep deprivation on cognitive abilities and behavior.
Sleep deprivation actually falls into three categories: (a) long-term total sleep deprivation, (b) short-term total sleep deprivation, and (c) partial sleep deprivation. As is to be expected, partial sleep deprivation has the least effect on neurocognitive functions and it is here that the contradictory results to fatigue since emerge. On the other hand, long-term total sleep deprivation and short-term total sleep deprivation both have a potentially destructive impact on both self-welfare with potential negative ramifications to social welfare in general. The more long-term the sleep deprivation the more negative the impact (Dumer & Dinges, 125). Even partial sleep deprivation, however, still has its consequences since, as recent experiments indicate, the accumulated effect of sleeplessness adds up to the condition of long-term total deprivation (ibid.)
c. Sleep deprivation and accidents
Sleep deprivation has not only been blamed for aviation accidents. Approximately, 20% of motor vehicle accidents are routinely attributed to sleepiness (Weiten, 185) as are an equally great proportion of mishaps in the workplace. Studies, for instance, have discovered that nighttime workers across the board routinely fall asleep on their jobs (ibid.). Whilst for some jobs this poses no problem (aside from running the risk of being fired), for others this may result in grievous risk. Examples, here, include responsibilities such as operating trucks, driving buses or trains, working as an air traffic controller, or running a punch press. Momentary lapses of attention can cost countless lives. Major disasters such as the running aground of the Exxon Valdez in Alaska, the nuclear accidents at Chernobyl and Three Mile Island, and the Challenger space shuttle tragedy, have been partially attributed to lack of sleep (Weiten, 185), and experts estimate that accidents reducible to sleep deprivation cost the United States economy over $56 billion annually and result in more than 24,000 deaths per year (Weiten, 2007).
IV. Reasonable measures that would have permitted operational objectives to be met whilst reducing the fatigue risk.
Airlines, FAA, and individuals themselves can all implement measures that will reduce the fatigue risk. In the case of the aircraft accident listed above, measures would have been simple: simply rotate sleep for each person and institute that each crewmember achieves a certain amount of sleep. Yet, sleep rotation is disallowed.
a. The FAA and regulation
The FAA, as the NTSB report correctly noted, was implicated in the accident since their reasonability lies in implementing, coordinating, and monitoring regulations for protection and safety of airlines and pilots. These regulations should include script that extends to fatigue management. Laws exist aplenty in regards to drugs. Alcohol, medical certification…