SMS Tools


Fatigue Risk Management System (FRMS)

FRMS is data driven process that monitors and managers the roster patterns of operational crew (mainly flight crew and cabin crew), after fatigue being cited as a contributing factor in many accidents.

Fatigue is a state of the individual and is mainly caused by sleep disturbance; irregular sleeping patterns, not enough rest time in between duties etc. It can also be a cause of underlying medical conditions.

Fatigue affects an individual’s response time and mental performance, rendering the person incapable of performing the demanding duties in aviation.

Using FRMS companies can expect the following results:

  • Flexibility of planning and rostering to better support-suit the commercial plan
  • Better rostering – meaning improved productivity
  • Achieving regulatory compliance
  • Pro-active safety operational risk management
  • Providing stability of lifestyle for crews – reduction in sickness, in attrition rates and absence

Many would argue why implement FRMS and not keep the regulation’s Flight Time Limitation (FTL) schemes. The answer to this is that FTL is basic and generic. It does not cover every operational aspect and the scientific validation was not performed for all kind of operations. FTL fails deeply to consider the circadian rhythms of the body as well as the jet-lag effects. FRMS allows for airline specific rostering, in collaboration and consultation with the crews. This optimises the roster, with more robustness in place, allowing for extra capacity and increased safety.

Many people can confuse fatigue with tiredness. Tiredness is a physical basic state that occurs daily and is nothing more than the need of sleep. However, fatigue means excessive tiredness due to accumulation and its improvement cannot be guaranteed after a sleeping session.

Fatigue can be transient, i.e. developed in a single duty period, in which case the recovery should be successful after a single rest period. On the other hand, cumulative fatigue, is an effect of prolonged sleepless periods, in which the individual is in a constant state of weariness and requires more than one sleep session to recover. Bearing in mind that sleep lost in one night, is not recovered simply but sleeping more the next night. Similarly sleeping credits cannot be accumulated for future use.

Causes of Fatigue:

  • Inadequate sleep
  • Working patterns
  • Mental boredom
  • Medical conditions
  • Long duties
  • Workload level


  • Memory degradation
  • Attention lost
  • Mood changes
  • Slips and Lapses (mistakes)
  • Increased risk appetite
  • Troubles focusing and problem solving
  • Mis-communication

Signs of fatigue can be both physical and cognitive – mental. The physical signs include feeling thirsty and hungry, whilst the cognitive include feeling angry for no reason, feeling stressful, feeling moody and a distinct lack of coordination in activities.

We can countermeasure the effects of fatigue by:

  • Advising our colleagues
  • Having a balanced diet
  • Managing our workload
  • Increasing exposure to light
  • Utilising rest periods during duty
  • Use of caffeine
  • Communicating our issue

Exercising regularly, having small naps throughout the day and being in lighted condition, are good habits that can delay the fatigue symptoms. Our dietary choices can have a strong effect on the symptoms as sugar, heavy meals and other stimulants will destroy our rest whilst milk or the subtle feeling of hungriness will help us.
A good routine to assist someone in sleeping, is what is called as sleep drive. This routine follows an individual’s daily routine prior sleeping, in a way as to convince the body that it is sleeping time. This routine would include avoiding disturbances, avoiding working and exercising prior bed, relaxation – meditation techniques, avoiding exposure to LED lights (tablets, smartphones), keeping the room dark and cool. An important point is to use the bedroom only for sleeping and not other daily jobs. This will create an association to the mind that bed equals sleeping.

Sleep loss is felt differently on each individual, as the amount of sleep required also differs across people. Sleep for adults ranges from 5-10 hours, averaging 8 hours per night. This is affected by sleep acquired during the day. Studies have shown that being awake for 18hours is the equivalent of Blood alcohol concentration of 0.05% (almost 1 unit) and if awake for 22 hours the concentration rises to 0.10% (in some countries over the legal driving limit).

One needs to be aware of the circadian rhythms of the body. The window of the circadian low is between 02-06am. A second window of circadian low is between 1-4pm. These are the times the body is craving for sleep. Likewise, the circadian high is in the afternoon around 6-8pm and sleeping at this time is forbidden as it will totally disrupt the night sleep.
Implementing an FRMS in the airline requires substantial planning. Crews and rostering personnel need proper training and awareness. A software is required for the collection of the fatigue reports and for the creation of the patterns. Before implementation across the network , a testing period is required, with the feedback system being highly important for the correct and safe operation of the system.