Boeing is developing revised software for an automated flight-control feature that can forcefully push down the nose of MAX aircraft and was implicated in a high-profile Lion Air crash in Indonesia this past October. But the work has dragged on months longer than initially anticipated following the accident, these officials said.
In addition to engineering challenges, they said, another reason for the delay stems from differences of opinion among some federal and company safety experts over how extensive the changes should be.
Originally, software updates were expected to be fairly straightforward and slated to be announced in early January. But since then, there have been discussions about potentially adding enhanced pilot training and possibly mandatory cockpit alerts to the package, according to one person briefed on the details.
There also has been consideration of more-sweeping design changes that would prevent faulty signals from a single sensor from touching off the automated stall-prevention system, officials said. But at this point, they said, such options appear to be losing favor among regulators.
The 35-day partial government shutdown—during which consideration of the fixes was suspended—also created further delays.
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Boeing favors a relatively simple solution that would primarily reduce the power and, under some circumstances, probably the repetitive nature of the flight-control system in question, called MCAS, according to these government and industry officials tracking the process. That appears to be the most likely outcome, they said, though no final decisions have been made. And the timing for an announcement remains fluid. The FAA is poised to mandate changes to the 737 MAX once there is a company-government consensus about the overall package.