Pilots never briefed on 737's new software

The chief executive of Boeing backed down Wednesday and called President Donald Trump to recommend that the United States temporarily take the company's best-selling jet out of service, following two deadly crashes in less than five months. Hours later, the president announced the plane had been grounded.

It was a stark reversal for Boeing, an industrial juggernaut that has enjoyed a decade of rapid growth and has deep ties in Washington.

The plane, the 737 Max, was deeply rooted in the company's psyche, a reflection of its engineering prowess and its enviable safety record. But it was also born of necessity as the company competed with its European rival Airbus.

The stakes for Boeing are high, with 4,600 pending orders that promise to bring in hundreds of billions of dollars. All that is at risk as regulators and lawmakers begin to investigate what went wrong with the Ethiopian Airlines flight and an earlier one on Lion Air. Some carriers are already reconsidering their purchases.

One area of focus is whether the training procedures on Boeing's jet, greenlighted by the Federal Aviation Administration, left pilots unprepared to deal with new software on the plane. When the plane was introduced, Boeing believed that pilots who had flown an earlier model didn't need additional simulator training and regulators agreed. The FAA didn't change those rules after the Lion Air crash in October and there are no plans to do so now.

Although the investigations are ongoing, preliminary evidence and data suggest potential similarities between the crashes, raising questions about the new software. Evidence at the Ethiopia crash site suggests there could have been a problem with the software, an automated system designed to help avoid a stall, which has come up in the Lion Air disaster.

When Airbus announced in 2010 that it would...