Objective data analyses to be available next year may offer the best chance yet for U.S. airlines, labor unions and regulators to come to terms with why individual cabin crewmembers sometimes work on flights suffering from what they consider severely degraded alertness. Then, mere opinions about the prevalence of fatigue serious enough to jeopardize flight attendant performance of safety-critical duties may carry less weight.
Airline and regulator interest in cabin safety-related studies by fatigue scientists and other specialists has been reflected in presentations at aviation safety conferences in anticipation of the results of the latest scientific inquiry by the U.S. Federal Aviation Administration (FAA). Cabin crew labor unions and other advocates of increased attention to the issue meanwhile hope that the evolving components of airline safety management systems (SMSs), such as aviation safety action programs (ASAPs) and fatigue risk management systems (FRMSs), will change the perceptions and the realities. Some U.S. airlines remain unconvinced that any research involving subjective judgments of fatigue by flight attendants should serve as the basis of regulatory changes or airline policy changes. For example, the Air Transport Association of America’s (ATA’s) position is unchanged from when it argued against a national flight attendant duty/rest/fatigue survey, which nonetheless has proceeded as ordered by a congressional appropriations committee in September 2004.1
ATA says that survey had been inadequately described in the FAA’s request for public comment on funding, and “the information obtained will not have practical utility, and the survey will not add to the FAA’s efforts to define, enact and support policies and practices that effectively manage fatigue in aviation operations.” Self-reported, subjective data cannot address questions of minimum crew rest regulations, reduced rest and potential regulatory revisions, the association said.
“The design and outcomes of any effort should include a clear path from study findings to an evaluation of whether further regulatory action is needed or warranted,” ATA said. “[Three decades of research] activities have created an extensive scientific foundation to understand fatigue in aviation operations, including policies and practices that can reduce fatigue and enhance sleep, performance and alertness. … Regardless of the actual participants or measures in specific studies, the findings can be generalized and applied to the human operators in aviation, whether pilots, flight attendants, air traffic controllers or mechanics. The outcomes related to sleep and circadian disruption, performance decrements and safety issues can be understood in the context of the human operators’ physiological design and generalized across people, settings and demands.”
Status of FAA Research
Current research on flight attendant duty time, rest periods and fatigue by the FAA Civil Aerospace Medical Institute (CAMI) comprises six follow-up projects that closely track recommendations that CAMI issued in July 2007.2 Based on limited information gathered in the time available, that report had listed sleep loss among the main factors in flight attendant fatigue.
This factor has been “shown in numerous studies to produce waking neurobehavioral deficits, which include vigilance degradations, increased lapses of attention, cognitive slowing, short-term memory failures, slowed physical and mental reaction time, rapid and involuntary sleep onsets, decreased cognitive performance, increased subjective sleepiness, and polysomnographic evidence [recordings during sleep of brain activity, eye movement and muscle tone] of increased sleep pressure,” the report said. “Cumulative sleep loss results in sleep debt, with chronic sleep deprivation, night after night, leading to cumulative and progressive performance decrements, even in healthy adults.”
Another main factor for flight attendants is circadian rhythm disruption, and a third is length of duty time. “Sleep loss and circadian rhythms interact dynamically to regulate changes in alertness and performance,” the report said. “The effects of jet lag and shift work are often characterized by symptoms such as disrupted sleep, changes in mood state, loss of appetite, gastrointestinal disturbance and disorientation. … Fatigue during international flights is due mainly to flight duration and time zone differences, while fatigue on domestic flights is related to total working hours, landing frequency (number of legs), workload and layover duration.”
In preparing the 2007 CAMI report, the researchers considered 17 flight attendant fatigue-related reports identified in the U.S. National Aeronautics and Space Administration Aviation Safety Reporting System (ASRS). “Some reports mentioned a lack of adequate rest or meals and listed general symptoms of fatigue,” the report said. “Flight attendants also reported that fatigue had affected completion of critical tasks and expressed a lack of confidence in their ability to handle unusual situations and/or perform adequate security duties.”
Research teams are scheduled to publish results from the current projects at the end of December, according to Thomas Nesthus, a research psychologist of the CAMI Human Factors Research Lab. One project is the national duty, rest and fatigue survey. The survey covers topics such as rate of occurrence of fatigue, working conditions in which fatigue occurred, consequences of fatigue, duty time and rest period schedules, and personal experience with airline practices.
Of survey questionnaires distributed to a random sample of 20,835 flight attendants, a total of 10,549 (51 percent) were completed and returned by the March 31 deadline for subsequent de-identified analysis. By mid-year, all data had been scanned and entered into a database, and were being analyzed, Nesthus said.
A parallel project is a field study, for which nearly 6,000 flight attendants volunteered, with an integrated assessment of computer fatigue models. Following approval of the data collection protocol for research on human participants, a research team under contract to CAMI during May randomly selected and trained a sample of 210 individuals from those who volunteered, stratified by type of operation and seniority, he said.
“Over a dozen of these flight attendants [so far] have received and have been trained on the use of the personal digital assistant–cell phone devices that we are using in our field study to collect data over a 25- to 30-day period,” Nesthus said. “This is a rather unique data-collection effort in regard to the limited attention that flight attendants have received in the research literature.”
Data collection began in June, focusing on fatigue during line operations. Participants wear actigraphy sensors on their wrists to detect body motions, pedometers and other devices that fatigue scientists have developed to measure the times and durations of every period that flight attendants are asleep and awake while on duty and off duty, among other objective data. The researchers planned to collect data to “explore the physiological and neuropsychological effects of fatigue, sleepiness, circadian factors, rest schedules, etc., on flight attendants … collect actigraphic data and light measurements to document flight attendants’ sleep/wake schedules and exposure to zeitgeber cues [natural environmental signals that synchronize the human body’s time-keeping system] from light,” the 2007 report said.
The participants also are completing sleep diaries to verify sleep/wake schedules. The field study includes validation of computer models for assessing flight attendant fatigue, which CAMI has called “an important step to understanding whether and how models could be used in conjunction with field operations.”
Also under way is a content analysis of more than 2,000 de-identified event reports for “fuller understanding of fatigue-related incidents” involving flight attendants. This project included a related survey of all members of airline ASAP event review committees; the survey response was approximately 46 percent.
For the other projects, researchers have collected and content-analyzed 50 international regulations and agreements pertaining to policies or practices that affect flight attendant fatigue “to see how other countries address these issues” and “to provide additional data to supplement other ongoing research”; collected, reviewed and summarized global scientific findings on fatigue training and countermeasures in multiple transportation modes, such as rail, highway and aviation; and drafted a report on prospective benefits of training flight attendants on fatigue issues and implementing fatigue countermeasures. Such training would be expected to comprise “exposure to information on fatigue, its causes and consequences, its interaction with circadian disruption, and how and when to employ countermeasures (scheduled naps, physical activity, social interaction, caffeine, etc.),” the 2007 report said.
Point of Reference
A 1995 U.S. air carrier incident investigated by the U.S. National Transportation Safety Board (NTSB) was noted in the 2007 CAMI report; others have cited the incident is a textbook case of a link between flight attendant fatigue and safety of flight. On July 9, 1995, the rear cabin entry door of an ATR 72 operated by Simmons Airlines as American Eagle Flight 4127 opened during climb after takeoff from Chicago O’Hare International Airport. The airplane received minor damage to the door structure and aircraft fuselage, and the lead flight attendant of two aboard was the only occupant injured. The flight crew landed at the departure airport without further incident.3
The lead flight attendant was treated for multiple contusions and abrasions to her left hand and forearm, and she said that her right leg and arm were sore. “This flight attendant stated she received these injuries when she threw herself forward onto the floor in an attempt to get away from the open door,” the report said. “She stated she hit her arm on a galley cart and the floor.”
The incident occurred on the last flight of her trip sequence. She said that she had closed the main passenger entry door and recalled checking that both indicators showed green, confirming that the door was locked. Loud humming occurred on takeoff. “She stated that once the door came open, her reaction was to get away from the open door,” the report said. “She stated she started yelling ‘help me, help me’ as she unfastened her restraints and dove forward into the aisle. Several passengers helped pull her into the cabin area and held onto her for the remainder of the flight.”
Investigators learned that the day before, she had flown three trips of her scheduled two-day sequence, then arrived at a hotel after 2200, obtaining approximately five hours of sleep before her 0500 wake-up call. That day, she flew seven trips on ATR 72s with unmodified doors. She had been scheduled to complete her eighth trip at 2105 on an aircraft with a new modified door. Her first recollection was that before takeoff she had conducted a door-locking procedure pulling the handle down rather than up, which would have been the correct direction for a modified door; she corrected her statement upon prompting from a union representative.
The Association of Flight Attendants–Communication Workers of America (AFA-CWA), along with other unions, has advocated government research on flight attendant fatigue, drawing from findings of an internal survey of members in 2005, said Candace Kolander, coordinator of air safety, health and security, and a presenter during the February 2009 International Aircraft Cabin Safety Symposium (CSS).
“Flight attendants typically still have to jump through hoops to say ‘I’m fatigued’ to their air carriers without disciplinary consequences,” she said. “If carriers want to have a complete FRMS, they can’t just look at fatigue in the front of the airplane, they need to look at fatigue in the back. We have made inroads. The response of volunteers to current CAMI research says that U.S. flight attendants are saying ‘We do believe this is a problem,’ and they want to ensure that the problem gets solved.”
Echoing ATA’s 2008 comments, AFA-CWA expects any changes to U.S. regulations to require a scientific basis, she said. Kolander said that prescriptive rules setting minimums — even for air carriers that demonstrate an equivalent level of safety from their FRMS — probably must continue, however, but with the misleading term “rest period” dropped in favor of “time off duty” or a similar term. This change would be recommended because “rest period” connotes time provided for sleep, but includes many routine activities such as riding on airport shuttle buses, checking into hotels, eating meals, bathing and dressing that reduce the sleep opportunity.
The airline practice of providing minimum regulatory rest periods between scheduled duty days has been perceived by AFA-CWA members as the main reason fatigue is an unresolved issue. Unless airline-labor agreements say otherwise, some flight attendants can be assigned to operate on patterns that can result in severe sleep debt, Kolander said.
The 2007 CAMI report said researchers at the time could not determine how widespread or problematic the practice is of scheduling flight attendants to operate according to the regulatory maximum for scheduled duty times — with the regulatory minimum rest periods and minimum subsequent rest — all based on science dating from the early 1990s. “To truly address the fatigue issue, regulations must be combined with sound and realistic operational practices, and supplemented, as needed, by personal strategies,” the report said.
CAMI also acknowledged that aircraft characteristics, airline work and safety culture, and individual factors complicate attempts to assess why fatigued flight attendants sometimes feel anxiety about their ability to effectively perform safety-critical duties. Age, gender, general health, level of cabin crew experience and “the highly variable personal/domestic situation including commuting requirements” were the individual risk factors cited.
“We try to work with the carriers to do fatigue assessments of our members,” Kolander said. “We also say to them, ‘Let flight attendants call in fatigued without discipline, but also recognize and mitigate the problem by providing fatigue training in recurrent training classrooms.’ Hopefully, the air carriers and the flight attendant community can come together and say, ‘Here are some of the circumstances where flight attendants can report fatigued without threat of disciplinary action.’”
How flight attendants typically commute and use their off-duty time to obtain the optimal seven to nine hours of sleep also enter the picture. “I believe that U.S. flight attendants are becoming more aware that what they do off duty can have a bad effect on cabin safety — that awareness is a good thing,” Kolander said.
Reports AFA-CWA received from fatigued flight attendants have said they had forgotten to arm their evacuation slides, Kolander told the symposium. “Others had forgotten that they had unaccompanied minors aboard the aircraft, and let them leave the aircraft on their own,” she added. “We also hear from flight attendants about being pulled over by police because many of the effects of fatigue actually do mimic drunk driving. Yet just prior to being stopped, at the end of a long duty day, they had been on board an aircraft ‘ready’ to operate the emergency equipment. If their behavior was a hazard on the road, why was operating in a fatigued manner not a hazard on board the aircraft?
“Such anecdotes argue for the need to address flight attendant fatigue, and there has to be a nonpunitive approach. Meanwhile, we are trying to educate our own members that fatigue is important and that they do have to take responsibility to educate themselves, which means getting the proper rest.”
Stop-Gap Energy Drinks
Acutely fatigued flight attendants sometimes have failed to communicate abnormal situations to the flight crew, said Lori Brown, an aviation science faculty specialist at the Western Michigan University and the second presenter to focus on the issue at the 2009 CSS. In one example from her files, she described the fatigued flight attendant aboard a McDonnell Douglas MD-80 who, before departure from Chicago, told the captain via interphone that a “secure ID” had been found during preflight cabin checks. The captain conducted the takeoff with the understanding that a lost employee identification badge — not a suspicious electronic device with a countdown timer — had been found. When the captain later understood the situation, he directed the flight attendant to place the device in the tail cone, the least-risk location on that airplane for a possible explosive device. The same flight attendant, however, then did not follow procedures for disarming and unlatched the tail cone, which fell to the runway during landing.
In recent conversations, some flight attendants have told Brown that the only fatigue countermeasure they routinely use is consuming extra coffee or, occasionally, carrying aboard and consuming cans of caffeinated beverages marketed as energy drinks. “To maintain alertness, the only real cure is to sleep,” she told the symposium. “Caffeine can be effective, but the important thing is strategic use at the proper time in the proper way. That takes education. They should not consume caffeine when alert but save it for times when they really start ‘sinking.’ Caffeine consumption also should be minimized because of the [mental] lull after consumption.” Energy drinks may contain forms of sugar that produce a short-lived feeling of extra energy, but are followed by a sudden drop in blood glucose level that can adversely affect in-flight performance, Brown said. A much-preferred strategy would be to stay hydrated in flight by drinking sufficient water, she added. Flight attendants also should follow news of scientific developments in using portable high-intensity lights as a countermeasure for disruption of circadian rhythms, she added.
Under a new EU-OPS regulation of the European Aviation Safety Agency (EASA) on flight time limitations for pilots and flight attendants, which took effect in July 2008, operators can seek approval of reduced-rest arrangements by demonstrating to the national civil aviation authority that the arrangements provide an equivalent level of safety. As part of related planning, the French Direction Générale de l’Aviation Civile (DGAC) issued a regulation enabling regional airlines to use FRMSs as a means of demonstrating the equivalent level of safety, according to an abstract of this work.4 EASA also turned to an international panel of fatigue scientists to address questions about managing flight attendant fatigue: the adequacy of provisions for flight duty period extension, including the need for additional conditions; the effect of rest location and rest facilities on sleep quality; provisions needed for extended flight duty period operations with in-flight rest and/or time zone crossings; and guidelines for a meal and drink opportunity.5
“The tasks of flight attendants require a sufficiently high level of alertness and cognitive performance to ensure safety and adequate response, especially in non-routine situations,” the panel’s report said, adding that U.S. flight attendants’ anecdotal perceptions of “increased perceived stress and workload due to changes in duties and responsibilities since 9/11 … appear equally applicable to European cabin crew and may further contribute to higher fatigue levels.”
The panel emphasized that some flight attendant fatigue may originate in arterial oxygen desaturation while cabin crews perform strenuous normal duties. “Flight attendants’ duties include considerably more physical activities than those of pilots,” the report said. “The high heart rate values that are recorded from cabin crew are usually associated with hard physical workloads. … Fatigue and lowered alertness in cabin crew may have negative effects on safety, although the degree of these effects is a matter of ongoing discussions. … Although the hazards of impaired functioning of cabin crew may differ from those of [dysfunctional] cockpit crew, the maintenance of optimal alertness and performance of cabin crew is of crucial importance. Therefore, the same duty and rest requirements should be applied for both cockpit crew and cabin crew.”
The panel recommended more time-efficient crew briefing strategies and preflight preparations as one method of extending rest periods for flight attendants, and said that flight attendants should not have to report more than 30 minutes before the flight crew, in the interest of maximizing their rest periods and mitigating their circadian disruption.
Unlike numerous studies of pilots’ success in obtaining sleep aboard aircraft, little is known about how well flight attendants sleep in economy seats, business class seats segregated from passengers or bunks. “No data are available about the relation between seating accommodation and sleep in cabin crew,” the report said. “Although it is assumed that physiological characteristics and needs of cabin crew are similar to those of cockpit crew, their work and augmentation schedules differ considerably from those of cockpit crew.”
Similarly, differences in physical workload mean that specific adjustments of minimum rest requirements may be necessary for flight attendants to operate with required levels of alertness during extended flight duty, the report said.
Recurrent allegations of insufficient time even to eat meals or drink water have to be addressed because inadequate energy and dehydration are incompatible with safe operations, and flight attendants also have a “need for occasional breaks from periods of continuous work,” according to the panel. Quick turnarounds that deny a meal opportunity “should be avoided or compensated with time during the flight to eat,” the report said.
Recent European fatigue research, considering both flight crews and cabin crews, includes an early 2008 survey of 223 cabin crewmembers commissioned by Jetairfly, a charter airline. Results were reported during a March 2009 international conference. “The key aims of the survey were to identify the extent to which crew felt fatigue was adversely impacting on safety, the aspects of crew performance being impaired by fatigue, and the features of the roster that were promoting fatigue,” the abstract said.6
“The majority of … cabin crew (83 percent) completed the survey … and cabin crew tiredness (35 percent) [was among] risks that the most crew identified as posing the greatest safety risk … 27 percent of cabin crew reported that fatigue adversely affected their work performance on ‘every’ or ‘most’ duties … [and] cabin crew cited increased irritability, distraction and loss of interest or motivation as the most frequently encountered effects of fatigue.”
The company identified several common issues on the flight deck and in the cabin, and then adjusted rostering and training. “[Pilots and flight attendants] identified transitions from late to early duties, long duty days (greater than nine hours), more than four consecutive early duties and roster changes as the prime roster-related fatigue hazards,” the abstract said. “The survey data, combined with the results of the statistical roster analysis, informed the design of a number of controls including training schedulers to more effectively manage aspects of the roster now known to promote fatigue, and company rostering guidelines that prevent rostering of early-to-late transitions. The results also guided the design of a crew fatigue and a [customized] fatigue awareness and countermeasures training program.”
- Berg, David A. ATA comments in response to FAA Request for Comments, National Flight Attendant Duty/Rest/Fatigue Survey. May 19, 2008.
- Nesthus, Thomas E.; Schroeder, David J.; Connors, Mary M.; Rentmeister-Bryant, Heike K.; DeRoshia, Charles A. “Flight Attendant Fatigue.” FAA Office of Aerospace Medicine. Final report no. DOT/FAA/AM-07/21, July 2007.
- NTSB. Factual report of incident no. CHI95IA215.
- Cabon, Philippe; Mollard, Régis; Debouck, Franck; Sarrazin, Jean-Christophe; Grau, Jean-Yves; Deharvengt, Stéphane. “Towards a Fatigue Risk Management System for the French Regional Airlines: Applicationsto the Reduced Rests and Split Duties.” A presentation to the 2009 International Conference on Fatigue Management in Transportation Operations in Boston, March 24–26, 2009. Publication no. LAA-EA 4070, Université Paris Descartes.
- Moebus, Philipp. “Scientific and Medical Evaluation of Flight Time Limitations.” Final report 1.0 no. TS.EASA.2007.OP.08 for EASA by Moebus Aviation, Sept. 30, 2008.
- Jackson, Paul; Bourgeois-Bougrine, Samira; Hilditch, Cassie; Holmes, Alexandra. “Guiding the Design of an FRMS: Part 1 — A Fatigue Survey of Crew Working for a Charter Airline.” Clockwork Research presentation to the 2009 International Conference on Fatigue Management in Transportation Operations.