On the 17th of April 2018, Southwest Airlines flight 1380 was climbing toward its cruising altitude over Pennsylvania when its left engine suddenly exploded, hurling pieces of the cowling in all directions. One fragment knocked out a window, causing an explosive decompression that sucked a passenger half out of the airplane. As the pilots struggled to regain control, flight attendants and passengers fought to pull 43-year-old Jennifer Riordan back inside the plane before she was ejected completely. Despite serious damage to their aircraft, the pilots managed to make a safe emergency landing in Philadelphia, saving 148 lives. But it was too late to save Ms. Riordan, who soon died of her injuries — making Southwest flight 1380 the first fatal accident involving a US airliner since 2009. As investigators sought to piece together the cause, they faced one critical question: why did an engine certified to contain debris in the event of a failure end up spitting out pieces that caused an explosive decompression and killed a passenger? The answer would turn out to lie in the very design of the 737’s engine nacelle, revealing a fatal flaw that had gone unnoticed for more than two decades.
