Boeing Co confirmed a report of a new software problem affecting its 737 MAX aircraft series, discovered during a technical review of the aircraft this month. Reuters described the new issue as one in which a software "power-up monitoring function that verifies some monitors are operating correctly."
In a statement cited by Reuters, Boeing reported it is working to resolve the new issue.
A monitor check is prompted by a software command when the aircraft or a system is "powered up"; in turn, that monitor indicates whether the system is functioning properly or if maintenance is required.
The 737 MAX has been Boeing's best-selling aircraft, but the program is on hold as Boeing waits for the Federal Aviation Administration and other aviation safety agencies to approve a revised flight-control software.
FAA and the other agencies are working with Boeing to document and test the new software.
The two crashes are understood to have been caused by a malfunction in the 737 MAX Maneuvering Characteristics Augmentation System (MCAS). MCAS is an "anti-stall" software meant to counter aerodynamic effects of the larger engines installed in the 737 as part of its redesign. The updated MCAS program is the basis for the testing Boeing is conducting now, in expectation of FAA's and other agencies' clearance to update the jets' flight-control programming soon, though the new software issue may delay that approval.
FAA reportedly is awaiting clarification from Boeing on how proposes to resolve the new problem.
American Airlines, Southwest Airlines, and United Airlines have extended their 737 MAX flight cancelations until June 3.
Boeing halted deliveries of new 737 MAX aircraft last April and more than 300 of the twin-engine, narrow-body jets are idled for airlines around the world, in response to two fatal crashes between October 2018 and March 2019.
In addition, Boeing is due to halt production of new 737 MAX jets this month, due to the backlog of undelivered aircraft.
