When American Airlines flight 191 began its takeoff run at the start of Memorial Day weekend 1979, everything seemed normal. As it had done on so many previous flights, the McDonnell-Douglas DC-10 roared across Chicago O’Hare’s Runway 32, bound for Los Angeles. This time, however, just as the plane became airborne, disaster struck. The left wing-mounted engine tore away from the aircraft and hurtled to the ground, rupturing hydraulic and electrical lines in the process. For a few brief seconds, the aircraft seemed to climb normally despite the damage, but then to the horror of hundreds of onlookers, the plane entered an uncontrollable roll to the left. Seconds later, with wings perpendicular to the horizon, the aircraft plummeted into a field less than a mile from the runway. This tragedy occurred because a change to a manufacturer’s maintenance procedure to improve cost-effectiveness damaged structure, allowing a design choice elsewhere to leave the aircraft uncontrollable in this unlikely but real scenario. Two-hundred seventy-three people lost their lives that day; their memory has been honored through improved maintenance standards, exhaustive design processes and strong communications across the industry.