Safer Skies

Crewmember fatigue is one of the leading causes for incidents and accidents in aviation. The Transport Safety Board of Canada, which published Aviation Investigation Report A11F0012, gives a prime example of what can happen because of crewmember fatigue.

According to the report, “When the FO [first officer] saw the oncoming aircraft, the FO interpreted its position as being above and descending toward them. The FO reacted to the perceived imminent collision by pushing forward on the control column. The captain, who was monitoring TCAS [traffic collision avoidance system] target on the ND [navigational display], observed the control column moving forward and the altimeter beginning to show a decrease in altitude. The captain immediately disconnected the autopilot and pulled back on the control column to regain altitude. It was at this time the oncoming aircraft passed beneath ….”

What prompted the FO to direct the aircraft downward and, thus, into the path of the oncoming aircraft? The result of the investigation into this incident, which fortunately did not result in loss of life, determined that, “The first officer was experiencing a circadian low due to the time of day and fatigue due to interrupted sleep, which increased the propensity for sleep and subsequently worsened the sleep inertia. Under the affects of sleep inertia, the first officer perceived the oncoming aircraft to be on a collision course and pushed forward on the control column.”

This was one contributing factor to the reaction of the FO to what he erroneously perceived to be a dangerous situation.

Successful FRMS

A successful fatigue risk management system relies on participation of key stakeholders from across an airline. The system’s process modules cannot operate independently. They should reflect an efficient, seamless integration of each dependent process with its predecessor.

A relevant contributor to crewmember fatigue is the structure and composition of crew rosters and individual crew-roster elements, for example, individual pairings.

“Night flights from North America to Europe have an inherent risk of fatigue for North American-based pilots,” according to the Transportation Safety Board report. “Most of these pilots fly a small number of night-time legs per month and revert to sleeping at night when not working. The circadian system of pilots who fly only a small number of night-time legs will not adapt to working at night, and these pilots are likely to display performance decrements during the night-time legs in spite of any countermeasures.”

In consequence, crew schedulers building and maintaining crew rosters (legal and in accordance with contractual agreements) itself is not sufficient to prevent crewmembers from experiencing fatigue.

Some specific reasons for crew fatigue include:

  • Working a schedule that touches between midnight and 6 a.m.,
  • Less than eight hours of quality sleep in the last 24 hours,
  • More than 17 cumulative hours awake since the last quality sleep period,
  • Continuous work time without adequate breaks.

Airlines, Aviation regulators (U.S. Federal Aviation Administration, European Aviation Safety Agency), international organizations (International Civil Aviation Organization) and industry trade bodies (International Air Transport Association) have recognized the relevance of fatigue and the importance of identifying, preventing and remediating crewmember fatigue. However, even without regulatory requirements, it is in every airline’s interest to implement policies and procedures in crew management to reduce the incidence of fatigue, support detection of fatigue and facilitate methodological evaluation of crew duties to prevent fatiguing assignments from being created and assigned to crewmembers.

Fatigue Risk Management System

A Fatigue Risk Management System (FRMS) is a comprehensive structure of interlocking processes that, together, support continuous improvement to policies and procedures aimed at mitigating risks to safety and security from crewmember fatigue.

The success of any FRMS depends on participation of all stakeholders, including:

  • Senior management,
  • Crew management department,
  • Chief pilot and flight attendant officers,
  • Crew planners,
  • Crewmembers,
  • Unions.
FRMS Is Essential

Fatigue, when paired with critical tasks such as takeoff and landing, which have no room for error, can prove a deadly combination. According to Dr. Steve Hursh from the Institute for Behavior Resources, a partner with Sabre Airline Solutions® for its fatigue risk management solution, fatigue can affect a pilot’s reaction time as severely as if he or she were operating the aircraft while impaired by alcohol.

For example, according to the National Transportation Safety Board of the United States, the crash of Colgan Air flight 3407, killing 50 people, was partly attributed to pilot fatigue.

Fatigue Risk Management Plan

Following the fatal crash of Colgan Air flight 3407, the U.S. Congress mandated a Fatigue Risk Management Plan for all U.S. airlines. Based on U.S. Federal Aviation Administration research, the plan provides education for pilots and airlines to address the effects of fatigue caused by lack of sleep, overwork, commuting and other activities. As part of the plan, airlines are required to train pilots about the potential effects of commuting.

“The pilots’ performance was likely impaired because of fatigue, but the extent of their impairment and the degree to which it contributed to the performance deficiencies that occurred during the flight cannot be conclusively determined,” as detailed in the aircraft accident report (NTSB/AAR-10/01, PB2010-910401). “Colgan Air did not proactively address the pilot fatigue hazards associated with operations at a predominantly commuter base.”

It is simply not enough for airlines to create and operate legal rosters and pairings according to U.S. FAA regulations. A second layer of analysis, such as FRMS, is needed to ensure that these “legal” pairings and rosters are not causing and promoting crew fatigue.

The Solution

Since there is no accepted physiological test, such as blood analysis, that can be applied to measure fatigue objectively, it is critical that symptoms linked with fatigue are recognized. Some symptoms include:

  • Measurable changes in performance,
  • Lapses in attention and vigilance,
  • Delayed reactions,
  • Impaired logical reasoning and decision-making,
  • Reduced situational awareness,
  • Poor assessment of risk or failure to appreciate consequences of actions.

Sabre Airline Solutions collaborates with the Institute for Behavior Resources and uses the SAFTE-FAST (Sleep, Activity, Fatigue and Task Effectiveness-Fatigue Avoidance Scheduling Tool) model, developed by the institute. The solution aligns with the ICAO’s requirement of “a data-driven means of continuously monitoring and managing fatigue-related safety risks, based on scientific principles and knowledge as well as operational experiences that aim to ensure relevant personnel are performing at adequate levels of alertness.”

When working with an airline, the consulting team at Sabre Airline Solutions uses a detailed approach for the assessment of current-state fatigue-management practices, crew planning procedures and fatigue reporting policies. The approach is applied to support the development of extensive recommendations for the implementation of a comprehensive FRMS for the airline. The company also provides industry-best-practice-based recommendations for the design and implementation of a state-of-the-industry FRMS.

An integral part of every engagement will be a detailed analysis of labor resource requirements resulting from any implementation of fatigue management procedures and policies. The results from this assessment are critical to support an end-to-end evaluation of the operational and commercial implications resulting from the introduction of a FRMS.

Sabre Airline Solutions Methodology

During each fatigue risk assessment engagement at an airline, Sabre Airline Solutions establishes and implements the above-mentioned components of a FRMS that provide the foundation for the continuous improvement to fatigue prevention, identification and mitigation. Its consulting services address each component of the FRMS cycle of business processes, including:

  • Fatigue risk management,
  • Policies and procedures,
  • Crew management procedures,
  • Crew fatigue reporting,
  • Measuring crewmember fatigue,
  • Assessing root causes for crewmember fatigue.

Airlines need to establish consistent policies and procedures for the mitigation of risks associated with crewmember fatigue. In addition to complying with applicable regulatory rules, such policies should take into consideration experiences made by other airlines and established as industry best practices.

Fatigue management policies and procedures established by an airline will guide procedures observed by crew management in building crewmember duties. Changes to crew management procedures can have an effect on labor resource requirements. The assessment of this impact needs to be part of any FRMS implementation project due to the long-term commercial implications from changes, especially increases in workforce resource requirements.

A Near Miss

As a result of sleep inertia, a flight officer on a Canadian aircraft mistakenly pushed forward on the control column after perceiving an oncoming aircraft to be above and descending toward his aircraft. Upon recognizing the error, the captain immediately pulled back on the control column to regain altitude. At that point, the oncoming aircraft passed beneath, causing a near miss.

Changes in crew management processes will also be reflected in the operations manual as well as union contracts. Inclusion of relevant fatigue-mitigating processes to manuals and contracts is required to inform crewmembers on behavior that they can influence and that reduces fatigue.

The success of any FRMS depends on crewmembers being able to report fatigue through an established reporting process. Fatigue reports need to be collected and evaluated objectively as part of the consecutive measuring process.

An efficient FRMS includes the application of objective measurement methods to identify fatiguing crew duties (rosters and pairings) as well as evaluate fatigue incidents reported by crewmembers.

Based on results from the measurement of crew fatigue, improvements to the fatigue management policies and procedures will be developed and implemented. The root-cause analysis represents the essential component that completes the FRMS as a tool for continuous improvement in the mitigation of risks linked to crewmember fatigue.


Sabre Airline Solutions uses the SAFTE-FAST model and assess potential fatigue embedded in pairings and rosters built by its airline customers.

SAFTE-FAST, the industry’s leading fatigue-assessment solution, is based on more than 20 years of fatigue-modeling experience. The model validates laboratory and simulator measures of fatigue. It has been tested and reviewed by peers, and it has the least amount of errors compared to other fatigue models. The model has been validated and calibrated by the United States Department of Transportation to predict accident risk and is accepted by the United States Department of Defense as the model commonly used to measure fatigue for fighter pilots.

SAFTE-FAST uses several metrics to score the pairings and rosters under analysis. These metrics include:

  • Effectiveness — Speed of reactions as percent of typical best;
  • Sleep Reservoir — The sleep component of effectiveness that depletes while awake and replenishes while asleep (performance reserve);
  • Fatigue Factors — Fundamental drivers of fatigue resulting from context of duty demands, sleep opportunities and time of day;
  • Fatigue Risk — Generally, low performance during critical phases of flight, take-offs and landings.

Using SAFTE-FAST, Sabre Airline Solutions provides airlines with a scientific indictor of whether their crewmembers are at risk of fatigue and, if so, where that risk is coming from. The tool:

  • Estimates real fatigue risk,
  • Shows detail of each schedule,
  • Calculates fatigue factors,
  • Illustrates conditions that lead to fatigue risk so mitigations can be implemented by a FRMS, as necessary.
The National Transport Safety Board

Reduce accidents and incidents caused by human fatigue in the aviation industry.

Using SAFTE-FAST, Sabre Airline Solutions consultants can help airlines evaluate the fatigue risk inherent in crew schedules. The model also allows the adjustment of the crew schedule and the underlying rest patterns based on information provided by crewmembers through fatigue reports.

For example, if a crewmember reports that he has not been able to sleep as usual in the last days since his sick child woke him up repeatedly during the night, the resulting loss of rest can be modeled with the solution and the impact on fatigue will be measured.

In developing an industry-best-practice-based FRMS and modeling each business process within the system using SAFTE-FAST, the recommended solution for a comprehensive FRMS will comply with regulatory requirements as applicable to the individual airline.

In addition, the recommended FRMS will provide transparency to all stakeholders in crew management, such as crew planners and schedulers, crewmembers, and senior management. This will facilitate efficient application of implemented procedures and policies by crew planners and schedulers, and will support acceptance of the established crew rosters by crewmembers.

Through the detailed resource requirements assessment, an airline will receive detailed recommendations on how potential increases to resource requirements can be mitigated through changes to crew management planning processes. Mitigation of resource requirement increases resulting from the implementation of a FRMS will support a cost-efficient introduction of fatigue management policies and procedures.

An airline must preemptively and continuously assess and monitor fatigue risk from the planning stage through post-operation analysis, at all levels of the organization through policies and procedures established as part of its FRMS. The airline must then use this ever-changing stream of data to alter and improve its operations as needed to maintain alert, healthy, happy and, most importantly, safe crew.

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