Fighting Fatigue

Building A Cost-Effective Strategy To Address Aircrew Fatigue

Aircrew fatigue is an ongoing hazard that can be mitigated through an application of existing research, data collection and analysis, as well as advanced crew-management technology.

By Hemchand Kochuttan and Douglas Mellor

Crew fatigue is an occupational hazard within the aviation industry. When fatigue sets in, aircrew may communicate poorly, become irritable and, more importantly, overlook serious activities or forget to conduct mission-critical tasks. Their decision-making abilities are reduced, and their ability to manage unexpected events may fail. They may even fall asleep for short periods, leaving the aircraft temporarily unattended. As a result, crew-fatigue-related incidents continue to be a fact of life.

Factors leading to fatigue have been clearly identified by the International Civil Aviation Organization (ICAO) in its guidance documents. Sleep is lost or reduced due to early starts, late finishes and working at night, causing a requirement to sleep at times when most people are normally awake. Moreover, crossing time zones shifts one’s body clock, leading to both disturbed and inadequate sleep for crewmembers.

In addition to managing fatigue within national prescriptive rules and guidelines on Flight Time Limitation, airlines can implement a Fatigue Risk-Management System (FRMS) to work outside these prescriptive rules to help address the crew-fatigue issue. Managing fatigue while operating within the prescriptive rules can be part and parcel of a company’s safety-management system. However, to work outside the prescriptive rules, regulators will insist that a Fatigue Risk-Management System is in place with greater regulatory oversight to examine the evidence supporting each safety case associated with each request for a derogation.

A typical safety case will provide evidence that each fatigue hazard has been identified and quantified. The size of the hazard can then be evaluated using customary management processes and solutions.

There may be many alternative solutions, and each of them may attract a different cost, so the safety team must be able to make the right call to recommend a solution that is affordable.

Furthermore, there should be a quality-assurance process surrounding management processes to ensure that any changes in the operating environment are taken into account and the processes remain stable. All of these initiatives will be reminiscent of the safety management systems already implemented at most airlines.

“FRMSC CONDUCTED A STUDY OF AIRCREW FLYING EAST AND WEST AND FOUND WHEN GOING WEST, EACH VOLUNTEER PILOT GOT SOME SLEEP DURING THE LAYOVER PERIOD ON ARRIVAL AT THE DESTINATION BEFORE THEY FLEW BACK TO BASE. HOWEVER, THEY ALL STARTED AND ENDED THEIR SLEEP PERIODS AT MOSTLY DIFFERENT TIMES, BUT DURING PART OF THE NIGHT, THERE WAS A PERIOD WHEN ALL THE PILOTS WERE ASLEEP AT THE SAME TIME. GOING EAST, THE SLEEP BEHAVIORS WERE COMPLETELY DIFFERENT, AND AT NO TIME DURING THE LAYOVER WERE ALL THE PILOTS ASLEEP AT THE SAME TIME. THE BEST RESULT ACHIEVED DURING THE STUDY WAS AROUND 60 PERCENT OF THE PILOTS WERE ASLEEP AT THE SAME TIME.”

Fatigue Risk-Management System

Every stakeholder involved in managing fatigue should have training to understand the causes of fatigue, the effects of fatigue on performance and which countermeasures are available. These stakeholders include those who have safety-critical occupations and may suffer from fatigue during their duty periods, those who are responsible for setting the schedules and those in management positions who are in operational oversight positions.

FRMS is a process that primarily detects and measures the fatigue hazard, as well as adopting a standard of acceptability of fatigue levels beyond which some action must be taken to mitigate high fatigue levels. In addition, the management team must use its training to understand enough about fatigue science to formulate an effective cost-efficient mitigation strategy.

If cost was not a constraint, most fatigue issues could be avoided relatively easily through, for example, a mix of additional aircrew, incorporating inflight sleeping accommodations or changing departure times. However, these are not always possible.

The pragmatic approach is for the management team to understand the causes of fatigue and determine cost-effective options so decisions can be made for mitigation that are safe for aircrews and passengers, as well as being financially appropriate and acceptable for an airline’s operations.

A clear understanding of Flight Time Limitations rules and a firm grasp of FRMS principles are vital for managing fatigue within the prescriptive rules. If a proposal for operating outside Flight Time Limitations rules is made within a FRMS, regulators will likely expect that they are made aware of the intended application before anything is started. They will also expect to be intimately involved with every stage of the process before each stage begins, and they will expect data to be collected to prove that the proposed approach to working outside the regulations will attract no more fatigue than if the company was working within the prescriptive rules.

Moreover, it is likely that fatigue studies to measure the possibility of fatigue experienced by aircrew will be conducted at some point during the process to confirm whether or not the proposal will work.

Measuring Aircrew Fatigue

Measuring fatigue for individual crewmembers can be involved. In doing so, normally, aircrew would spend a month recording their level of fatigue when on and off duty, as well as when and for how long they have slept during this time. In addition, a subset of the aircrew would wear an Actiwatch to objectively record when they are sleep. Some may even be asked to complete periodic reaction-time tests or wear internal probes to measure the position of their body clock. These studies can be very intrusive, onerous and expensive, as well as take time to accomplish.

Rather than conducting such relatively complex studies, many airlines find it quicker, easier and a lot less expensive to use data already collected by the Institute of Aviation Medicine in Farnborough, England, to model their proposed operational schedules to identify and scale any inherent fatigue hazards.

Since 1980, the institute has continually measured aircrew fatigue, and it has compiled a formidable catalogue of study data that is available in a mathematical model called System for Aircrew Fatigue Evaluation (SAFE). Ideas for mitigating fatigue when working outside the regulations or simply trying alternative options for mitigating fatigue within problematic schedules can be tested in the model. This allows the elimination of sub-optimal solutions, leaving only the most promising alternatives to be tested in any fatigue studies that may be required.

THE SAFE MODEL USES THOUSANDS OF PILOT SCHEDULES AND RETURNS FATIGUE SCORES EVERY 15 MINUTES THROUGHOUT EACH DUTY PERIOD, TAKING INTO ACCOUNT TRANS-MERIDIAN TRAVEL, CUMULATIVE FATIGUE, CREW COMPOSITION, ON-BOARD NAPPING AND OTHER VARIABLES. THE MODEL ESTIMATES SLEEP PERIODS – BOTH START TIME AND LENGTH – WHICH CAN BE MANUALLY ADJUSTED AS PART OF THE MODEL’S INTERACTIVITY DESIGN. THIS ENABLES AIRLINES TO FIND OPTIMUM SOLUTIONS FOR PROBLEMATIC ROSTERS. IN ADDITION, SLEEP PERIODS CAN BE INSERTED, CHANGED OR DELETED AS NECESSARY.

System For Aircrew Fatigue Evaluation

Using the SAFE model, an airline simply uploads aircrew schedule data so fatigue scores for every 15 minutes of duty can be calculated for all aircrew throughout all of their duties covering a maximum 12-month period. With this data, all fatigue hazards due to scheduling can easily be identified. The model determines how many hazards exist and where they are, as well as their size. This is a quick, easy solution that identifies and measures any fatigue hazards in the planned or actual aircrew schedules.

The model is also useful for incident investigation as it can be tuned to reflect the reported sleep of any aircrew involved and determine if fatigue was a likely cause or contributing factor.

In addition, by running aircrew schedules through SAFE, a safety manager can identify fatigue hazards caused by the construction of the schedule. If hazards are non-existent and a member of the aircrew still states that he or she is fatigued, the cause of the fatigue is likely to be found in other areas of the crewmember’s life or health that transcend the schedule.

This may be a result of the quality of hotels used or other factors within the operation. It may also be caused by lifestyle issues or even the crewmember’s state of health. There is always a reason for fatigue, and SAFE makes it easy to determine whether or not it relates to the schedule, thereby setting the direction of subsequent exploration to discover the root cause.

Rating Fatigue Levels

National Aviation Authorities (NAA) provide guidance on acceptable levels of fatigue that is mostly derived from ICAO recommendations. There are many scales that are used to define fatigue, and the most popular is the Samn-Perelli scale; a 7-point scale where 1 is de ned as fully alert and wide awake, while 7 means exhausted and unable to function.

Scientists often point to 5 on the scale to be the point where something in the schedule should change to reduce the likelihood of fatigue. For pilots, airlines may expect an increase in fatigue report receipts when fatigue levels approach 5, and around that level, concerns emerge that levels of vigilance or reaction times are becoming too degraded to be considered safe. Of course, airlines will choose their own threshold scores to reflect their acceptable risk levels.

CREW FATIGUE CONTINUES TO BE A GROWING PROBLEM IN AVIATION. TO ADDRESS THE CREW-FATIGUE ISSUE, AIRLINES CAN IMPLEMENT A FATIGUE RISK-MANAGEMENT SYSTEM TO WORK OUTSIDE THE FLIGHT TIME LIMITATION PRESCRIPTIVE RULES AND GUIDELINES.

Management Processes

Management processes are integral in the fatigue-management strategy. With local NAA approval, airlines may adopt the same processes for FRMS that are used for their Safety Management Systems (SMS) if they intend to manage fatigue within prescriptive rules. The purposes of both management systems (SMS and FRMS) are the same – to ensure safety – therefore, airlines may opt to begin with existing, known processes to avoid duplication and minimize risks. Working outside the regulations requires intimate engagement with the airline’s NAA.

By managing fatigue in a consistent manner, airline safety managers will be able to address another risk factor. Aircrew will be satisfied that their management has recognized this perennial, inherent problem associated with their occupation, which will lead to improved staff retention, thereby avoiding the significant costs attributed to staff turnover.

Moreover, the benefits can be sizeable for airlines as well. A number of airlines have approached their insurers to demonstrate that they have identified their fatigue hazards and are managing them. This has resulted in significant discounts to their insurance premiums.

Sabre has adopted the SAFE model as part of its crew management-solutions portfolio, including Sabre Crew Manager and Sabre Crew Control, by developing integrated workflow to help airlines manage aircrew fatigue risks.