Boeing Finds New Software Flaws on 737 Max

Boeing Co. has identified two new software problems with the grounded 737 Max that must be fixed before the jetliner can carry passengers again.

The issues involve the flight-control computer and don’t affect the plane’s estimated return to service in mid-2020, Boeing said in an email Tuesday. The Max’s software has been undergoing a redesign after being linked to two fatal crashes that prompted a worldwide flying ban more than a year ago.

The new flaws deepen the engineering challenge for Boeing as it tries to return its best-selling jet to the skies. One of the problems involves “hypothetical faults” in the computer’s microprocessor, which could lead the plane to climb or dive on its own, Boeing said. A safety system on the Max caused the jet to dive automatically in both accidents, but the problems aren’t related, Boeing said.

The other newly revealed fault could potentially cause the autopilot to disengage as the aircraft prepares to land. Neither problem has been observed in flight, but the software changes will eliminate the possibility that they could occur, the company said. The modifications can be incorporated into the plane at the same time.

In a separate statement, the U.S. Federal Aviation Administration said it has been in contact with the company about the issues.

The new software problems were reported earlier by Reuters.