Designing Safe Highly Automated Human-Machine Systems Using an Stpa-Based Approach: A Case Study

Because modern aircraft are increasingly reliant on automation, it is essential thatthese aircraft include appropriate human-automation interactions to ensure safeflight. However, it can be challenging to design these interactions using currentmethods. This paper demonstrates how a design approach based on Systems-Theoretic Process Analysis (STPA) enables more in-depth consideration ofhuman factors engineering and system safety when designing the pilot-automationarchitecture for an advanced rotorcraft concept. First, STPA is used to derive thecontrol responsibilities needed to safely operate the aircraft. Then, alternativeways to allocate those control responsibilities to the human pilot or automationare compared to identify safety and human factors-related benefits and tradeoffsto help select a preferred pilot-automation architecture. This STPA-basedapproach thus improves a designer’s ability to consider human factors and systemsafety in an integrated manner and design safety into a system from the beginning.