Fatigue in Transportation Forum
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Chair, Transportation Safety Board of Canada
June 27, 2018
Check against delivery.
Slide 1: Title slide
Thank you very much for the opportunity to speak here today. It's a real pleasure, especially since Montreal is my hometown—I was born here—and McGill University is my alma mater.
I've been asked to talk about fatigue in accident investigation. However, before I begin, there are likely some people in the audience today who may not be familiar with the Transportation Safety Board of Canada or TSB for short, so I will start with a very brief introduction.
Slide 2: About the TSB
The TSB is an independent federal government agency whose mandate is to advance safety in four federally regulated modes of transportation: air, marine, pipeline, and rail. We do this by carrying out investigations into selected transportation occurrences, to understand not only what happened, but more importantly why it happened, so that steps can be taken to reduce the risk of similar accidents happening again.
We are not a regulator, nor do we assign fault or determine civil or criminal liability.
Slide 3: Fatigue in investigations
At the TSB, we recognize that fatigue is a hazard in any 24/7 transportation system. And because it is a hazard, it must be managed. That's why, in almost every TSB investigation, it's an issue we consider.
- First of all, was it present?
- And second, did fatigue have an impact on performance?
Slide 4: How do we analyze fatigue?
At the TSB we have a number of human factors investigators to help us analyze fatigue. Those investigators use a 3-step process. I've already covered the first two: identifying whether fatigue was present—for instance by studying the 72-hour work / rest history of those involved (even longer if appropriate)—and then seeing if fatigue actually played a role.
The third step is to determine if organizational practices in place were sufficient to effectively manage the risks of fatigue.
When we investigate for fatigue, we look primarily at the following six risk factors:
- Acute Sleep Disruption
Acute sleep disruptions are reductions in the quality or quantity of sleep that have occurred within the prior three days.
- Chronic Sleep Disruption
In addition to acute sleep disruption, sleep quantity or quality disruptions that are sustained for periods longer than three consecutive days also increase the risk of fatigue.
- Continuous Wakefulness
A third fatigue risk factor is being awake for too long, commonly referred to as prolonged or continuous wakefulness. 22 hours of continuous wakefulness (less if working a night shift) can be considered "the point at which fatigue causes almost all aspects of human performance to start to decline".
- Circadian Rhythm Effects
Because of a daily, or circadian, rhythm, the human body is physiologically ready for sleep at night and for activity during the day. Changing sleep-wake patterns too quickly can cause circadian rhythms to desynchronize and this can lead to performance impairments. Working at a time of day at which our body is expecting sleep can also impair performance.
- Sleep Disorders
Many sleep disorders result in higher than normal levels of fatigue if they are untreated or not managed properly. Three of the more common sleep disorders are insomnia, obstructive sleep apnea and periodic limb movement disorder.
- Medical and Psychological Conditions, Illnesses, and Drugs
Some illnesses, medical conditions (e.g., pain), and psychological conditions (e.g., depression, anxiety and high levels of stress) result in poor sleep quality and reductions in the amount of sleep. As with medical and psychological conditions and illnesses, all drugs (including over the counter and prescription medications) should be considered when investigating fatigue.
I'd now like to look at three recent TSB investigations, each of which involved fatigue, albeit in different ways.
Slide 5: TSB Marine investigation report M16P0378
On the evening of October 11, 2016, the U.S.-registered tug Nathan E. Stewart departed Ketchikan, Alaska, bound for Vancouver, British Columbia. The tug was pushing an empty tank-barge, the DBL 55, and together the two vessels formed what's known as an articulated tug-barge unit.
At 11 p.m. on the evening of October 12, the Nathan E. Stewart's second mate arrived in the wheelhouse to take over navigational watch duties from the master. Already tired at the start of his shift, the second mate had likely been awake for about 11 hours—mainly because, like the rest of the watchkeepers, he'd spent the previous two-and-a-half days working a challenging "6-on, 6-off" schedule: alternating periods of six hours on duty, followed by a six-hour rest period.
As I'm sure many of the people here today are aware, this type of schedule is well-known for disrupting the normal sleep-wake cycle, and for limiting opportunities to obtain sufficient "restorative" sleep. And the numerous deficiencies of this schedule have been documented by various studies and experts internationally.
At any rate, as the second mate began his watch, he was alone on the bridge, and he made his workstation comfortable by adjusting the bridge chair and the lighting, turning up the heat, and putting on some light music. Shortly after midnight, he made one course alteration, but then fell asleep … and the tug-barge unit's course and speed went unchanged for the next 46 minutes until it struck and grounded on a reef, approximately 10 nautical miles west of Bella Bella.
After several hours of pounding from the waves, the tug's hull breached, and it released over 110 000 litres of diesel fuel before eventually sinking later that day.
The TSB's investigation revealed that the second mate, although able to consistently get 4 hours of good quality sleep in the mornings, was unable to fall asleep in the afternoons or evenings. Put simply, he was dead tired at the time of the occurrence. And when he fell asleep, it was unintentional: he simply didn't anticipate that the turning down the lights, putting on some light music, and getting comfy was going to lead to an accident.
Slide 6: Recommendations
As a result of this accident, the TSB made two recommendations. The first was for education and awareness training. For instance, if watchkeepers have a better understanding of what fatigue is, the factors that cause it, and of the practical actions that can be taken to eliminate or minimize its effects, there may be a significant reduction in the number of fatigue-related marine occurrences. That's why we recommended that Transport Canada require that watchkeepers whose work and rest periods are regulated by the Marine Personnel Regulations receive practical fatigue education and awareness training in order to help identify and prevent the risks of fatigue.
Our second recommendation was aimed at vessel operators, the people who have the primary responsibility for managing the safety risks within their own operations. We think they should do more than just make their employees aware. That's why we are recommending that Transport Canada require commercial vessel owners to implement a comprehensive fatigue management plan—one tailored specifically for their operation.
Slide 7: TSB Aviation investigation report A11F0012
The second fatigue-related occurrence I'd like to look at happened in 2011, when an Air Canada Boeing 767 was flying from Toronto to Zurich. On board were 95 passengers and 8 flight crew. Approximately halfway across the Atlantic, during the hours of darkness, the aircraft experienced a 46-second "pitch excursion." This resulted in an altitude deviation of minus 400 feet to plus 400 feet from the assigned altitude of 35 000 feet above sea level.
The seatbelt sign had been selected "on" approximately 40 minutes prior to the pitch excursion, yet 14 passengers and 2 flight attendants were injured. The flight continued to destination, whereupon 7 passengers were sent to hospital and later released.
Slide 8: A11F0012: What really happened?
The First Officer (FO) felt fit for flight at the time of reporting for duty at 1935 Eastern time, which likely coincided with a circadian high. However, the interrupted sleep obtained in the 24 hours immediately preceding the flight increased the likelihood the FO would feel fatigued and need rest during the overnight eastbound flight, particularly as a circadian low was reached. The FO fell completely asleep during the controlled rest period, which also indicates the FO's level of fatigue.
With a view to providing a substantial rest, the captain allowed the FO to rest beyond the 40–minute maximum that was set as a defence against entering slow–wave sleep.
Yet the 75–minute rest that ensued increased the probability of entering slow–wave sleep, which can increase the severity of sleep inertia if a person is awakened—especially if the rest occurs at a circadian low and when the person is fatigued.
At about this time (0155), the FO awoke following the Captain's radio communication with ATC. To avoid the FO being startled, the captain twice pointed out the relative position of an oncoming aircraft. This occurred approximately 1 minute after the FO had woken and was most likely suffering from the strong effects of sleep inertia. The FO was not in a state to effectively assimilate the information from both the instruments and from outside the aircraft, or to effectively provide an appropriate response. Under the effects of sleep inertia, the FO was likely confused and disoriented and perceived the aircraft on an imminent collision course. Consequently, the FO pushed forward on the control column to avoid the collision. The FO quickly realized the error because the traffic appeared to be moving down in the visual field, which did not make sense. By that time, the captain had reversed the control movement to return the aircraft to the previous altitude.
Slide 9: A11F0012: Findings as to cause
Slide 10: Factors to consider
We live in a 24/7 world. Many employees have to work overnight. Pilots face an additional challenge because overseas pilots also have to adapt to changing time zones.
One of the issues is that flying overnight, when our body naturally wants to sleep, and through a natural circadian low which occurs during the early morning hours, can lead to performance decrements.
Many organizations with shift workers have adopted formal fatigue risk-management plans, which include:
- Education and awareness training and strategies
- Policies for napping and controlled rest
- Scheduling practices and, in the case of airlines, use of a relief pilot
In this case, the operator was trying to do the right thing by implementing a "controlled napping" policy. Allowing naps and controlled rest while on duty can help restore a crew member's alertness. However, if the procedures aren't followed as outlined, it can also lead to another issue, known as sleep inertia. The TSB report says:
Sleep inertia refers to the post–sleep performance decrements that occur immediately after awakening. Although the duration of sleep inertia is usually short, from 1 to 15 minutes, some deleterious effects can last 30 minutes or longer.
One of the detrimental effects of sleep inertia is a decrease in cognitive processing speed. For example, it takes longer than normal for a person experiencing sleep inertia to filter out incongruous visual information.
So … short naps —that is, of a 20- to 40-minute duration—are better, to avoid going into slow-wave sleep; and it is important to allow sufficient recovery time after a nap to offset sleep inertia's effects.
Slide 11: Controlled rest
This information informed Air Canada's policy on controlled rest. However, the findings from this investigation also reinforce the need to adhere to the procedures for controlled naps, to avoid the unintended consequences that might otherwise occur.
Slide 12: TSB Rail investigation report R16C0012
The third example I'd like to share with you today took place in early 2016.
On 18 February 2016, at approximately 0623 Mountain Standard Time, a Canadian Pacific Railway freight train derailed 13 cars in Alyth Yard, Calgary. There were no injuries, and no dangerous goods were released.
The TSB's investigation found that the locomotive engineer's working memory and vigilance were likely limited due to fatigue, and that this contributed to the improper train handling that led to the derailment. (In this case, specific-train handling requirements relating to the maximum locomotive throttle for the occurrence location were not followed.) We also found that the likely cause of his fatigue was poor-quality sleep in the 2 weeks prior to the occurrence, plus the fact that he had been awake for at least 23 hours at the time of the accident.
So how did that happen?
Here's what we learned during our investigation:
The LE went to bed at approximately midnight on 17 February 2016 and woke up at approximately 0700 that morning. However, the LE had not been sleeping well during the 2-week period prior to the occurrence, frequently waking and experiencing difficulty falling back asleep. He had been occupied throughout the day on 17 February, attending to personal commitments. The LE had been anticipating a call to go to work in the afternoon. However, when he consulted the train line-up later in the day, he learned that his call would likely not come until much later than originally anticipated. By the time the call came, at about 2020, the LE had not taken the opportunity to sleep.
CP permits employees to book unfit when not sufficiently rested, provided they do so prior to receiving their call. In this case, the LE did not book unfit.
At the time he accepted the call, the LE did not feel fit to report for work. However, he feared discipline if he refused duty, given that he had previously been disciplined, in the form of a temporary suspension, for pattern absenteeism. As a result, the LE accepted the call.
Slide 13: R16C0012: Lessons learned?
So what happened after the investigation? Were there any lessons learned?
Unfortunately, the answer does not appear to be yes. As our report states:
- CP conducted an internal investigation … [and] determined that the cause of the incident was improper use of locomotive throttle.
- CP's post-incident investigation synopsis stated that the LE acknowledged the following to the company: "He was fit and well rested when he accepted the call … He forgot about the … operating restriction and was remorseful for being responsible."
- CP's internal investigation did not include a review of the LE's sleep history and did not identify any systemic issues that may have contributed to the LE forgetting about the operating restrictions.
Slide 14: Fatigue management: a Watchlist issue
Fatigue is pervasive in today's society, especially in the transportation industry—so much so that it's now an issue on our 2016 Watchlist, which identifies 10 key safety issues that need to be addressed to make Canada's transportation system even safer.
Since 1994, sleep-related fatigue has been identified as a contributing factor or as a risk in 23 TSB railway investigations— 19 of them involved operating crew members on freight trains. These 19 investigations represent about 20% of the 94 rail investigations conducted since 1994 in which a human factors aspect of freight train crew activities was a primary cause.
Even though the railway industry and Transport Canada have known sleep-related fatigue to be a problem for over 20 years, the initiatives taken to date have been inadequate to fully address the issue.
As a result, fatigue continues to pose a risk to the safe operation of trains, particularly freight trains, which move 70% of the country's surface goods, including dangerous goods.
Slide 15: Fatigue management: what's next?
This issue will remain on the Watchlist until:
- Transport Canada completes its review of railway fatigue management systems; and
- Transport Canada and the railways implement further actions to effectively mitigate the risk of fatigue for operating crew members on freight trains.
Slide 16: Not everybody is on the same page
Last year—and again earlier this year—some segments of the aviation industry suggested—inaccurately—that the TSB did not consider fatigue to be a concern in aviation. These comments, originally made as part of industry consultations between aviation representatives and Transport Canada regarding draft regulations on pilot flight and duty times, have since been clarified, but in some quarters, the misperception persists.
So I'll just make a few brief points about that:
- First, and to be clear, the TSB has made a number of findings about fatigue in aviation investigation reports over the years. In some cases, fatigue was causal, whereas in others it was found to be a possible risk for future accidents.Footnote 1
- Second, when drawing up our Watchlist for 2016, the Board did indeed consider whether fatigue should be a multi-modal issue. However, we did not have sufficient data at the time to support the inclusion of fatigue as a systemic problem in any mode beyond rail transport.
- Here, though, is the real takeaway: just because a specific safety issue is not on the TSB Watchlist should not be interpreted to say that it is not an issue that needs to be addressed, or that nothing more needs to be done to reduce the risk. Because there's always more that can be done.
Slide 17: Conclusions
And that little aside nicely brings me to my conclusion today.
Obviously, at the TSB we recognize that fatigue can affect performance. We see it in investigation after investigation, across all modes of transport. And because of the effect that fatigue has on performance, two things need to happen.
First, employees in all modes and in all industries need to be made aware. Whether that's education, awareness training, or something else, they absolutely must know what can happen when you try to do your job while fatigued. They also need to know what factors can make it worse, and what countermeasures might make it better. And I'm not just talking about a mid-shift stretch or a late-night cup of coffee. I'm talking about things like workplace lighting, the way you sit—or stand—whether you work by yourself or with others, and when your shift starts and ends. The list goes on.
The second thing that needs to happen is that employers and operators—the people who have the primary responsibility for managing the safety risks within their own operations—need to have a plan, and that plan has to have concrete elements that reduce the risks of fatigue. And not just a general plan, either—it won't cut it to say you'd like your employees to just "get more rest". No, the plan must be specific to the elements that create or exacerbate fatigue within their specific operation.
If we can take those two steps, then it is my hope that we will have gone a long way to reducing the risks that exist—and to making transportation safer … for everyone involved.
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