Modeling performance and alertness: the QinetiQ approach.

The basis of the QinetiQ alertness model used at the heart of the System for Aircrew Fatigue Evaluation (SAFE) free-standing software tool is described. A number of extensions to the basic model that are applicable to the civil aviation environment are outlined, based on the analysis of eight studies involving sleep diaries gathered from pilots undertaking a range of duty schedules. The relationship between subjective alertness and performance of laboratory tasks is described and it is concluded that different tasks are affected differentially by fatigue.