The Boeing 737 MAX airliner, which began service in 2017, was involved in two fatal accidents, Lion Air Flight 610 on October 29, 2018, and Ethiopian Airlines Flight 302 on March 10, 2019, that resulted from a malfunction of the aircraft's new automated control feature, the Maneuvering Characteristics Augmentation System (MCAS). The grounding subsequently became the longest ever of a U.S. airliner. As of January 2020, another 400 newly-manufactured aircraft await delivery to airlines pending the aircraft's return to service.