The Boeing Company

Two lithium-ion battery events in nine days exposed a gap between the safety proposition certified for the Boeing 787 and the behavior of its installed batteries. The first produced fire in a parked Japan Airlines aircraft at Boston; the second forced an All Nippon Airways 787 to divert and evacuate at Takamatsu. Investigators later found that a single-cell internal short could escalate into cell-to-cell thermal runaway, while the initiating defect could remain destroyed or unresolved. The fleet returned through a three-layer redesign that reduced initiation risk, impeded propagation, and contained and vented a failure outside the aircraft. That was an effective operational recovery, but it also changed the accountability question: certification could no longer depend on assuming propagation away; it had to demonstrate that even an unexplained cell failure would not threaten the aircraft.

Boeing 737 MAX MCAS is a risk and accountability case because two fatal crashes, a global grounding, public investigations, criminal-resolution records, regulator return-to-service actions, and continuing safety-governance scrutiny showed how safety-critical automation can shift practical control among manufacturer, regulator, airline, pilot, and passenger. The public record matters because certification evidence is not merely paperwork; it is the proof that design assumptions, human factors, training, delegation, and repair decisions protect people who cannot inspect the automation carrying them.