https://phys.org/news/2019-03-boeing-safety-feature-standard-max.html > The people spoke on condition of anonymity because Boeing and federal regulators are still discussing details of the upgrade to the Max fleet, which was grounded worldwide after a second deadly crash this month in Ethiopia. > The cause of the accidents has not been determined, but investigators probing the crash of a Lion Air Max jet have focused on an automated system designed to use information from two sensors to help prevent a dangerous aerodynamic stall.