Boeing 737 MAX grounding

Boeing's 737 MAX, an updated version of its decades-old 737 family designed to compete with Airbus's more fuel-efficient A320neo, incorporated a new automated flight-control system called MCAS meant to counteract the plane's tendency to pitch upward under certain conditions. Investigators found that MCAS relied on a single sensor without adequate redundancy, and when that sensor malfunctioned on a Lion Air flight in Indonesia in October 2018 and an Ethiopian Airlines flight in March 2019, the system repeatedly forced each plane's nose downward until pilots lost control, killing a combined 346 people. The US Federal Aviation Administration initially resisted grounding the jet even after the second crash, but reversed course within days as evidence of the crashes' similarity mounted and other regulators worldwide — the EU, China, Australia and others — moved first to ban the plane from their airspace. By March 18, 2019, all 387 delivered 737 MAX aircraft were grounded globally, a status that lasted about 20 months while Boeing redesigned the flight-control software, and the crisis cost Boeing tens of billions of dollars and lasting damage to its reputation for engineering rigor.