How Complex Systems Fail: Lessons from Boeing’s 737 Max 8 Crashes

Dr Sean Brady

November 2025

Published in the SCL Journal: Autumn 2025 

When we examine systems, we tend to believe that everything that happens has a definite, identifiable cause and effect. We expect that significant failures happen because of significant causes, and vice versa. The author looks at the Boeing 737 MAX 8 crash in 2018, and introduces the sand pile model, explaining that taking a complex systems approach provides a more useful way of viewing these types of incidents. The paper asks us to re-examine our more traditional views on cause and effect, and to look more closely at the sand piles we build in our own projects and organisations. Are the systems we’ve built tending towards a critical state, just waiting for a grain of sand to bring them tumbling down?

Introduction – Complex Systems – The Sand Pile Model – Boeing, Airbus and the A320neo – Developing the 737 MAX 8 – MCAS – The Extension of MCAS – The First Crash – The Second Crash – Closure

The author: Dr Sean Brady is a forensic engineer and the managing director of Brady Heywood

Text: 9 pages