Preparing Safety Cases for Operating Outside Prescriptive Fatigue Risk Management Regulations.

Area of Science:

• Aviation safety
• Human factors in transportation
• Occupational health

Background:

• Transport operators must justify fatigue risk management outside regulations.
• A structured safety case method is detailed for compliance.
• This enables operational flexibility in crew rest scheduling.

Purpose of the Study:

• To present a method for constructing a successful safety case for operating outside prescriptive fatigue management regulations.
• To demonstrate how this method allows for flexible rest break choices for pilots.
• To validate the effectiveness of the proposed safety case approach.

Main Methods:

• The safety case method involves defining scope, risk assessment, mitigation strategies, and ongoing monitoring.
• Scope included analyzing 4151 scheduled flights to estimate fatigue risk.
• Risk assessment utilized existing literature and pre-regulation pilot data (6% chose third break).

Main Results:

• A prospective survey (N=280) confirmed the third rest break is not consistently superior for sleep or fatigue.
• The safety case successfully summarized existing fatigue monitoring and mitigation systems.
• Established systems for hazard identification and risk assessment were incorporated.

Conclusions:

• The presented method has been successfully used in other safety cases.
• Evidence requirements for safety cases should adapt to the perceived risk level.
• Experience with fatigue risk management systems should inform evolving safety case evidence.