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Overview of FRMSc

Migrating from API v1 to API v2?

See our Migration from v1 to v2 guide to learn what we have changed in v2 API and how you can use them.

What is FRMSc

FRMSc are experts in the implementation of fatigue management of safety-critical operations. Our knowledge and expertise, gained over 40 years, have been used to shape regulations best practices and develop a suite of biomathematical models to predict fatigue levels and risks of work schedules. Our models are being used by regulators and organisations worldwide in industries such as aviation, rail, health, and others. Our biomathematical models are validated from real-world scientific studies with targeted data collection specific to different occupations. Our fatigue models incorporate sleep deprivation, circadian rhythm, sleep inertia, workload and job attention. The models predict fatigue risk based on work/rest schedules, job and occupational demands.

Our models help identify fatigue and fatigue risk in work schedules, improving safety, operational efficiency and employee wellbeing. The models, which are a data-driven, proactive and flexible approach to managing fatigue, can be used independently, as part of existing regulations or as part of a Fatigue Risk Management System (FRMS).

How do the models work?

Our biomathematical models use rosters to predict the fatigue levels and risk of different work schedules. The nature of the occupation dictates what data needs to be uploaded into the different models.

In its simplest form, an individual’s work schedule comprises one or more duties over a given period. Each duty has characteristics, such as start and finish date-time and workload. A roster comprises one or more schedules. Roster data is uploaded into the model where our sophisticated, mature algorithms analyse the schedules, construct sleep patterns and predict levels of fatigue and risk, considering factors including workload, cumulative fatigue, circadian rhythm and time zone shifts.

The models output fatigue scores at regular intervals throughout the duty, allowing scheduling/rostering/crewing managers to assess rosters for fatigue risk.

What are the models in use?

Our biomathematical fatigue models comprise:

  • SAFE: Developed in collaboration with the aviation industry, this validated model predicts fatigue and duty risk of pilots for commercial, business, cargo and air taxi operations.
  • CARE: Developed to reflect the specific challenges of cabin crew, this model estimates fatigue and alertness levels of flight attendants.
  • FRI+: Upgraded version of the original HSE Fatigue Risk Index which was developed by FRMSc personnel, this model assesses fatigue risk from shift work patterns and is the fatigue model mandated for use by UK Network Rail.
  • FRI PRO: Enhanced FRI+ model with advanced features incorporated from the SAFE and CARE models, such as individualised sleep and performance predictions, and fatigue mitigation strategies.

SAFE for pilots: Use cases

As an airline operator, you are legally bound to adhere to the Flight Time Limitations from your regulator or approved derogations. Your organisation may choose to use a biomathematical model for its safety operations, which are part of its Fatigue Risk Management System (FRMS) or Safety Management System (SMS).


The SAFE web application provides a set of software tools to analyse a schedule of duties for alertness issues.

  • Upload rosters in Excel or CSV format, matching the SAFE upload template.
  • Analyse the schedule to identify duties with high fatigue and/or risk by viewing the fatigue display, sleep reservoirs, and time zone acclimatisation.
  • Proactively identify fatiguing schedules and make changes to the schedules in SAFE to test different scenarios to mitigate fatigue risk.
  • The SAFE algorithms analyse the pilot schedules based on their duty pattern, sector flow, and time zones. They construct a sleep pattern based on the duty schedule, in-flight rest where applicable, and analyse the entire schedule to calculate fatigue scores every 15 minutes while working and the duty risk metric.

SAFE Application API

Automation and integration with existing business processes is possible through the SAFE Application API.

  • Send roster data from your existing applications and rostering software directly into SAFE for analysis.
  • You can log into your web version of SAFE to view the analysed roster, identify duties with high fatigue and/or risk and view the analysis of fatigue, sleep reservoirs and time zone acclimatisation.
  • Optimized for bulk processing.


For real-time integration the SAFE Application API may not be fast enough. The SAFE Swift API offers integration with the algorithm, returning fatigue and/or risk scores only so we can deliver results in real-time.

  • Send roster data from your existing applications and rostering software directly into SAFE for analysis.
  • The SAFE algorithms analyse the pilot schedules taking the same approach as explained above. But rather than storing the data for viewing and analysis in our web version, the fatigue scores and duty risk metrics are returned to the rostering software for presentation and storage by the third-party rostering software provider.
  • This approach provides a snapshot of maximum fatigue scores and duty risk metric for each duty without providing the detailed analysis and ability to edit the schedules within the web version of SAFE.
  • This approach provides fast analysis and return of fatigue scores and supports near real-time updating of schedules.

SAFE as Third-party Service

Where your rostering software provider provides it, you can use their interface to access our biomathematical models. This way, you can access fatigue scores calculated by SAFE through your rostering software provider to see the impact of your scheduling decisions on the pilots’ fatigue and the risk levels.

  • Create your rosters in your rostering software.
  • Your rostering software provider has an integration with us in the backend, which they use to share the roster data with us.
  • The SAFE algorithms analyse the pilot schedules taking the same approaches as explained above.
  • Your rostering software provider receives fatigue and risk information and either shares that information, as is, with you or appends additional information to it before sharing with you.

CARE for cabin crew

These approaches for pilots using SAFE can also be applied to cabin crew using CARE.

Storage Integration Solution

We have also created a storage integration solution that automatically imports rosters into the SAFE model when the roster is dropped to a cloud storage location. For more details on this, please contact us.