Managing fatigue in a regional aircraft operator : fatigue and workload on multi-segment operations

Abstract

Introduction: With the constant increase in air travel every year and the downfalls of the World’s economy, airline managers face the need to optimize resources with the goal of reaching profit and reliability targets. This leads to higher utilization rates in commercial aircrews, with more hours of work and the consequence of less sleep and off time. As such, pilots and cabin crew face an increasing number of sleep disturbances, with the consequent alertness impairments and reduced performance. The concept of fatigue resumes these issues and has recently been addressed by several studies and documents, which prove its hazards and identifies them as risks to a flight’s safety. The main goal of this study is the methodic identification of fatigue in a regional aircraft operator that, although not suffering from night circadian disruption has a major rostering structure of multi-flight operations with flights in the early hours of the day. Methodology: The universe and the sample size of this study are equal and correspond to 52 airline pilots, 27 Captains and 25 First Officers, all males and an average age of 39.2 years old. The methodology used in this research consists of two interconnected principles: objective fatigue measurement, using bio-mathematical modeling through the SAFE model and subjective fatigue measurement through a 3 week daily survey applied to real operations, allowing the measurement of individual fatigue in the beginning of work and at top of descend on the last flight of the day. The survey was complemented by an adapted version of NASA’s TLX workload measurement scale, allowing a more complete analysis of an additional fatigue cause that has impact in multi-segment operations. A questionnaire was also distributed in order to identify any variability factors that could influence the measurements and limit pilot’s capabilities and performance.Results: Results were determined by setting a methodic approach to schedule analysis, with 365 days of planned pilot rosters processed. Areas of high risk were identified, in particular on the early hours of the morning and the evening and on days with more than 4 sectors. With the surveys and when comparing both measurements, SAFE model predictions stay short of 5 in the Samn-Perelli Scale (Moderately tired. Let down.) whilst pilot reported fatigue values represent a 6 on the same scale (Extremely tired. Very difficult to concentrate.). A high relation was also found between the increase of fatigue, the number of sectors and time of day, revealing that workload might be caused by multi-segment operations and a hazard to what can be considered an acceptable level of safety to risk management in flight operations. Conclusion: A new approach to workload in the fatigue and safety settings should be considered, and further research should strive to look at the impact of workload in multi-segment operations. This should all lead to new hazard identification and risk mitigation practices to be in place, joining flight safety and rostering departments in better and more robust schedules, with of course increased safety levels and better overhaul performance.

Orientação : Anabela Simõe

Original document

The different versions of the original document can be found in:

• http://hdl.handle.net/10437/7195