Boeing’s back-to-back crashes involving the same 737 MAX 8 model have few parallels in modern aviation history

Boeing’s twin disasters involving its newest single-aisle jet add to the history of rare aviation accidents that call into question the safety of the planes themselves.

Back-to-back incidents where the aircraft is probed as a possible culprit are far less common than the usual litany of pilot error, mechanical failure, weather, war and terrorism.