The 737 is an excellent airplane with a long history of safe, efficient service. Boeing’s cockpit philosophy of direct pilot control and positive mechanical feedback represents excellent human factors. In the latest generation, the 737 Max, Boeing added a new component to the flight control system which deviated from this philosophy, resulting in two fatal crashes. This is a case study in the failure of human factors engineering and systems engineering.

Successful systems are created by engineers who understand and design to the ultimate objectives of the project. When we lose sight of those objectives we start making design decisions based on the wrong criteria and thus create sub-optimal designs. Scope creep, group think, and simple convenience are frequent causes of this type of variation. An effective design assessment tool is a touchstone by which we can evaluate the effectiveness of ongoing design decisions and keep the focus on the optimal solution.

HSI is a natural part of the systems engineering process. It adds minimal up-front cost for significant benefits and cost savings. Optimizing the system for performance and lifecycle cost benefits the customer. Ensuring early consideration of HSI factors reduces the risk of costly rework to the contractor. Delivering a system which is mission effective with reasonable lifecycle costs benefits everyone.