Boeing exec Mike Sinnett reportedly floated the possibility of just such an event at a November meeting with American Airlines pilots, weeks after the Indonesia crash and months before the Ethiopian crash in March. However, he dismissed concerns by claiming that pilots could easily recover in such a situation. The worst that would happen would be a need to "return to base," he said.

The aircraft maker has declined to comment, although acting FAA head Daniel Elwell implied that the Ethiopian Airlines pilots weren't completely honoring required procedures. It's not clear that pilot error led to the crash, though, and Ethiopian investigators found that the crew was following Boeing's instructions but couldn't override the software.

The fixed software is complete, so this might not happen again once the 737 Max is clear to resume flights. However, this and previous reports of a flawed safety analysis suggest that Boeing wasn't aware of just how serious the flaw was until the Ethiopian Airlines crash prompted widespread concern.