DC 6 Through 737 MAX – Identifying Unreliability with In-service Precursors to Avoid the First Crash

Before the first design flaw related crash or emergency landing in an aircraft fleet, there are less severe events that signal a reliability problem. The significance of these precursor events is easily recognized in hindsight during crash investigation; however, they are often unnoticed or dismissed prior to a crash or emergency landing. Intentional use of precursors provides an early opportunity to recognize a reliability issue and to eliminate even the first design related crash or emergency landing. This paper reviews the DC 6, DC 8, DC 10, Boeing 787, and Boeing 737 MAX. These planes had design flaws that existed on the day they were placed into service, and they caused major events – crashes and emergency landings. These major events were preceded by precursor events that occurred after the fleet was placed into service, but before the first major event. Of The 937 fatalities caused by the design flaws in this review, 96% are shown to have been avoidable with attention to in-service precursors and data analysis of the precursor and major event intervals.