Boeing Has Known About This Landing Bug for Two Years

The Federal Aviation Administration has opened an investigation into a software fault in the Boeing 737 MAX 8 and MAX 9 that can affect the aircraft during an aborted landing. In a narrow set of circumstances — a missed approach flown on a precision approach with the autopilot engaged, where the crew has made changes to the pre-programmed flight plan — an issue in the flight management computer can cause the vertical navigation mode to disengage and hand the aircraft to a less sophisticated form of automated pitch control. Boeing has been aware of the behaviour for roughly two years.

The company notified 737 MAX operators of the issue in late August, telling them at the time that it did not constitute a safety risk. Boeing has said it shared information reinforcing existing pilot procedures for handling such cases, and that its engineers are working on a software update that will address the problem permanently. That framing — a known quirk, contained by procedure, with a fix in progress — is the industry’s standard posture on a latent defect, and it is exactly the posture regulators are now examining rather than accepting.

The regulatory timing is the sharpest part of the story. The fault surfaced publicly only days before the FAA was expected to certify the 737 MAX 10, the largest and last of the four MAX variants to be approved, and roughly a month after the MAX 7 cleared certification. An open investigation into flight management computer behaviour on the two variants already in widespread service is not a neutral backdrop for signing off a third, and the review could push the MAX 10’s entry into service further to the right after years of delay.

None of this changes what a passenger should do, because there is nothing a passenger can do: go-arounds are routine, flown by trained crews, and the scenario described requires a specific combination of automation mode and flight plan editing. What it does change is the regulatory picture around the world’s most-produced airliner family. Every MAX operator now has an FAA investigation running against equipment already in its fleet, and airlines that have ordered the MAX 10 have a further reason to keep their delivery assumptions loose.

Sources: CBS News, NBC News