A Fatigue Risk Management System (FRMS) has been defined by ICAO as "a data-driven means of continuously monitoring and maintaining fatigue related safety risks, based upon scientific principles and knowledge as well as operational experience that aims to ensure relevant personnel are performing at adequate levels of alertness".
Historically, the aviation industry has taken a regulatory approach to fatigue prevention through the specification of flight and duty time limitations in a Flight Time Limitations (FTL) Scheme. This is done by limiting the number of hours aircrew can work and specifying the minimum rest time which is required before commencement of each flight duty period. The purpose of an FRMS is to support the safe application of such FTL Schemes by recognising the need for aircrew be adequately rested before commencing and during flying duties by facilitating both proactive and reactive interventions in relation to the implementation of FTL Schemes.
It has been recognised through research that there are a number of causes of fatigue including:
- Lack of adequate sleep within a specified rest period.
- Daily body rhythms, known as circadian rhythms, which may impact the quality of sleep and / or affect performance when awake.
A fatigue risk management system allows operators to effectively utilises their FTL Scheme whilst taking into account the above effects. Fatigue models may be used to proactively. Demonstrated safety benefits have included increased crew member alertness, better work life balance amongst crews and a reduction in absenteeism attributed to fatigue. In addition to this, an FRMS may facilitate increased productivity and rostering flexibility.
Computer models can be used to predict average performance capability from sleep/wake history and normal circadian rhythms. They can help operators understand the likely effects on performance of sleep obtained before and during trip patterns.
An effective FRMS is data-driven and routinely collects and analyzes information and reports related to crew alertness as well as operational flight performance data. It helps to control the risk associated with both transient and cumulative fatigue.
The FRMS can be established as a standalone system or as a part of the Safety Management System (SMS).
Several examples of successful FRMS are in place today:
- New Zealand has the longest experience with the application of FRMS principles to FTL-based rostering. In 1995, New Zealand Civil Aviation Authority Regulations were changed to allow operators to use either a standard FTL scheme or an approved variation on that scheme justified by an assessment and appropriate response to additional factors that might cause fatigue.
- Singapore Airlines introduced a FRMS in 2003 after commencement of ultra long haul (ULH) flights between Singapore and New York. The company was allowed to operate these flights as a result of scientific recommendations based on biomathmatical modelling.
- easyJet was the first major short haul airline to be issued with a Regulatory dispensation from their FTL Scheme in order to operate a new crew roster pattern which took account of FRMS principles. That roster featured a sequence of 5 early starts, 2 days off, 5 late starts, 4 days off in place of the previous cycle of 3 early starts, 3 late starts, 3 days off).
In 2008, ICAO added FRMS to Annex 6 and provided guidance to Regulators on how to implement and oversee FRMS.