Night moves

A 24 Hour Society

It used to be so simple. When the sun dipped below the horizon we retreated to the safety of our caves, curled up under a bear skin beside the gentle glow of a fire and slept until the radiant beams in the east signalled a new day. We awoke rested and restored, ready to hunt prey and outrun predators. It was a pattern of rest that endured for millions of years until the industrial revolution and elec-trical power cracked the door on a completely new way of conducting society. Working by night was no longer to be the lonely realm of the night watchman or the ship’s lookout; it was to become a way of life.

In a couple of centuries we have flown in the face of our natural history and asked our bodies and brains to adapt to a 24 hour society. As aviators, the 21st century demands are ever growing as timetables increasingly aim to have the traveller at their destination by business hours. The ramification is that the airlines need to provide a service that involves flights throughout the night, in the hours col-loquially known as ‘back of clock’ when the human body would much prefer to be at rest.

Flying The ‘Red Eye’

Across a broad spectrum of industries, work-related fatigue is being recognised as a hazard to safety. Lack of sleep, poor quality of sleep, working for extended periods or in conflict with the body’s natural rhythms of rest can erode the ability to perform tasks, both mentally and physically. In the work-place, studies have shown that this erosion of performance equates to a higher risk of accidents occurring.

In aviation, crews are called upon to demonstrate dexterity of both the mind and body. Being asked to do so through the night

Transcontinental flights in the ‘back of clock’ hours from Perth to the east coast are recognised as particularly difficult in a fatigue sense.

introduces another factor into the equation and recent investigations by the Australian Safety Transport Board (ATSB) reveal that “…negative safety outcomes have been attributed to fatigue-related factors” (ATSB 2002, 2004).

There are few night-freight pilots who haven’t dawdled into the noddy world of ‘microsleeps’ at some time, and instances of aircrew reporting to be “weary” or “exhaust-ed” at the end of a night sector are relatively commonplace. However, such instances are anecdotal and subjective without firm data to support the event. As such, there is no base line from which to commence addressing the issue.

There have been attempts to relate per-formance degraded by fatigue in relation to performance degraded by alcohol consump-tion. Studies have shown that around 17 hours of continuous wakefulness can equate to a blood alcohol reading of 0. 05 per cent and after 24 hours the figure will double to 0. 10 per cent (Dawson and Reid 1997; Williamson and Feyer 2000).

Another study by Lyman and Orlady in 1980 examined just over 2000 aircrew error reports and found a fifth involved fatigue. Not surprisingly, the trend reflected an in-creased problem between midnight and 6am during the high workload phases of descent, approach and landing.

In domestic commercial operations, trans-continental flights in the ‘back of clock’ hours from Perth to the east coast are recognised as particularly difficult in a fatigue sense. These flights generally depart the western capital around midnight and arrive in Sydney, Brisbane or Melbourne around dawn, placing them centrally in the profile of the Lyman and Orlady study. Often, the crews are then called upon to fly an additional sector to one of the other eastern capitals before finishing their tour of duty at around 9am Eastern Standard Time.

As with the growth of the ‘24 Hour Society’, demand for the transcontinental sec-tors will continue to rise. The challenge facing operators, regulators and the ATSB alike is to ensure that the conduct of these opera-tions is in the safest manner possible. Civil Aviation Order 48. 0 (Flight and Duty Time Limitations) has long been utilised to ensure crews are adequately rested, but is it totally appropriate for ‘back of clock’ operations? In an effort to answer such questions and quantify the effects of fatigue, a study was un-dertaken to specifically examine “The Impacts of Australian Transcontinental ‘Back of Clock’ Operations on Sleep and Performance in Commercial Aviation Flight Crew. ”

The Frms Study

Commissioned by the ATSB, the study was conducted by the University of South Australia in conjunction with airline crews who had been granted permission by their company to participate. The University of South Australia is no stranger to FRMS (Fatigue Risk Management System) research, having been integral to the far-reaching program undertaken in association with the Australian and International Pilots Association (AIPA). By far the most extensive project in the field, it sought to examine FRMS across the entire range of operations around the world, including the longest sec-tors and worst instances of ‘east-west’ jet lag.

The Australian transcontinental study col-lected data from the crews over a fortnight, examining the week before and the six days after flying a transcontinental ‘back of clock’ sector. The data was assembled from three sources, firstly, an activity monitor wristwatch that recorded the wearer’s body movement. Next, sleep and duty diaries were kept in which the crew member recorded periods of sleep, time of duty and ‘self assessments’ of such factors as sleep quality and fatigue levels before and after their rest. Finally, there was a ‘five minute psychomotor vigilance task’ (PVT) to gauge neurobehavioral response. Conducted on a hand-held PDA over the 14 days and during periods of low activity in the cruise, the test calls for the crew member to press a button as quickly as possible when the visual cue appears.

Within the study, comparative levels of data were measured between crews operating the single ‘back of clock’ sector and then a secondary sector to an east coast destination. Over 80 volunteers offered to contribute

For the second sector sleep, subjective fatigue and response times were all notably degraded in relation to the baseline.

to the study, but by the time roster changes and operational issues had played their normal role, the complete data set consisted of just over 20 pilots. Even so, the results in terms of sleep and wake patterns, ‘subjective fatigue’ and neurobehavioral response yielded interesting results.

The Findings

Overall the findings differed greatly from the baseline drawn from pilots operating normal daytime sectors. In the 24 hours prior to duty, the pilots gener-ally had slept more than their daytime counterparts, indicating that the major-ity had an additional rest period imme-diately before signing-on for the night. However, by the time they touched down on the east coast for the first time, they had registered significantly lower levels of sleep in the preceding 48 hours than they would have in a two day period of ‘normal’ rostering. When asked to complete a ‘secondary’ east coast sector, the prior sleep level was greatly reduced.

This erosion of prior sleep for the second sector was indicative of the degradation in all aspects of the study. Performance in the Palm PVT test was also degraded on the second sector, with response times notably slower than the baseline figures. In relation to subjective fatigue, the pilots’ self-assess-ment reflected that they were varying between okay and very lively before the first sector, which was in line with the baseline findings, but before departing on the second sector this had deterio-rated to moderately tired. Arrivals didn’t fare as well with pilots describing their state as moderately tired before their first east coast arrival, but between moderately and extremely tired for the second approach.

Overall the results recognised that there were significant differences in a number of areas with reference to sleep patterns, subjective fatigue and the PVT tests when ‘back of clock’ operations were compared to baseline, daytime duty. On the first sector, these “differ-ences were of a magnitude that were unlikely to impact on flightcrew per-formance and overall safety. ” However, for the second sector, subjective fatigue and response times were all notably degraded in relation to the baseline.

The differences between individual pilots were also highlighted. In any crew, there will often be a disparity between the amount of sleep gained before a ‘back of clock’ tour of duty. Some are able to sleep during the day, some are not. This variance between individu-als presents a further challenge to the design of any FRMS and highlights the fact that CAO 48. 0 may not be able to cover all types of operations with its blanket approach to flight and duty times; nor can it be expected to be. The 24 hour society has led to numerous changes to all aspects of our life, and managing flightcrew fatigue is simply another.

The Future And Frms

These studies are the first step towards developing a strategy. Before they were undertaken, flightcrew fatigue was not quantified and con-sequently could not be countered. Through the global AIPA study and the transcontinental ‘back of clock’ report, rule makers and schedulers alike now have a tangible insight into the effect of flights in conflict with the body’s natural desire to rest. But it’s early days.

“The FRMS is in the formative stage of implementation with the assistance of the University of South Australia,” Virgin Blue’s Michael Young, general manager aircraft operations, explains. “It is too early to attribute any changes in scheduling or rostering to the FRMS at this stage. ” He also sees that “any rule set, for example CAO 48, is but one component of a successful FRMS. Reliance on a rule set to solely determine rostering and scheduling practices is likely to reduce with the advent of the FRMS model. ” Qantas Captain Richard Woodward from AIPA also explains that the find-ings of their mammoth FRMS study are in the process of being converted from a statistically based report into a more operationally orientated docu-ment. From this report there will be the ability to review FRMS issues on long haul routes as well as domestic ‘back of clock’ operations.

In both cases, Australia is at the forefront of FRMS research and the airlines and crews that participate in such studies should be congratulated. It is pioneering work that recognises that our brave new world comes with complications that need to be ad-dressed. This proactive approach seeks answers to the questions arising from the grey world of fatigue and has the potential to impact positively on air safety. All flight operations are not the same, the FRMS study quantifies this and offers the ability for scheduling to be tailored to the specific rest needs of the route or timetable. Ultimately it will lead to better rested and better performing crews, though in our 24 hour world it is unlikely that the ‘red eyes’ will ever totally disappear from ‘back of clock’ operations. o The author wishes to recognise the efforts of Matthew Thomas, Renee Petrilli and Gregory Roach from the University of South Australia for their study, “The Impacts of Australian Transcontinental ‘Back of Clock’ Operations on Sleep and Performance in Commercial Aviation Flight Crew”.