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White Papers

SAFTE-FAST as a Supporting Tool for Fatigue Investigation

Looking at work schedule data, time of day, and sleep history, SAFTE-FAST can provide a picture of the fatigue risk during a work-related incident.


This white paper describes, in general terms, how to use SAFTE-FAST to estimate fatigue risk to determine whether fatigue should be considered a contributing factor during a safety investigation.

Sleep and Fatigue During Covid-19 Humanitarian Missions

In 2020, Azul Linhas Aéreas Brasileiras embarked on record-setting humanitarian relief flights from Brazil to China for which there was no prior precedence.

Modeling in SAFTE-FAST was used to determine optimal departure times considering high levels of alertness, high sleep reservoir, and alignment with circadian interactions. SAFTE-FAST was also used to predict in-flight rest opportunities from best to worst-case scenarios. During the flights, the volunteer crew kept personal sleep diaries and wore IBR’s Zulu Watch to collect actual sleep data.

Workload Calculator

Our workload calculator was defined to be validated with subjective rating tools like the NASA TLX scale. Download our Workload White Paper to learn more.

Zulu Watch Validation

Read how our Zulu Watch compared to polysomnography and see why airlines have adopted the Zulu Watch as a means to collect actual sleep data.

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