A go-around is the one manoeuvre every airline pilot rehearses until it is boring, because when it happens for real it is anything but. Full thrust, nose up, gear and flaps coming in, a new clearance on the radio. It is precisely the moment Boeing has now admitted that some 737 MAX software can quietly hand a piece of the job back to the crew.

On 26 September 2026 The Wall Street Journal reported that Boeing had found a flaw in the flight management software of its newest 737 variants. Boeing confirmed it, the FAA said it is convening a Corrective Action Review Board, and the timing could hardly be worse: the problem sits in the software for the 737 MAX 7 and the 737 MAX 10, the two models Boeing has spent years trying to get across the certification line.

What Actually Goes Wrong

The scenario is narrow. According to Boeing and the reporting by CBS News and AeroTime, it needs a precision approach flown with the autopilot engaged, followed by a go-around, followed by the crew changing the pre-programmed flight path. In that sequence VNAV can drop out. The autopilot keeps flying, but falls back to a simpler pitch mode instead of following the vertical profile the flight management computer had planned.

VNAV is the part of the flight management system that works out the climbs and descents needed to meet the altitude constraints along a programmed route. Lose it and nothing falls out of the sky. What changes is the workload: the pilots must manage the vertical path themselves, at low altitude, while they are already reconfiguring the aircraft, talking to air traffic control and setting up for another approach.

That is why the FAA is treating it seriously even though Boeing says existing procedures cover it. A Corrective Action Review Board is the FAA process for deciding whether an issue is a safety problem that needs mandatory action. The agency has said it will act immediately if the review finds one.

Nearly Two Years in the Making

The awkward part is the timeline. CBS News reported that an airline first flagged the behaviour to Boeing in November 2024, and that Boeing concluded in February 2025 that it was not a safety concern. Further information from operators later prompted a formal safety review, and the FAA was notified in September 2026. Boeing told operators about the issue a month before it became public.

According to CBS News, Southwest Airlines and United Airlines declined to take deliveries with the affected software, while Alaska, American, Southwest and United all said their in-service MAX fleets do not run the problematic versions. The FAA put its own position in careful terms.

Why the MAX 7 and MAX 10 Can't Afford This

The MAX 7 is the smallest member of the family and the MAX 10 the largest. Both have been stuck in certification for years, and every month of delay pushes back aircraft that airlines ordered long ago. The MAX 7 now holds its FAA type certificate; the MAX 10 is approaching the final stages. Both are targeted for customer deliveries in 2027, according to AeroTime.

Bloomberg reported that Boeing acknowledged the software issue may delay the arrival of its latest narrowbody models. A permanent fix had been planned for 2028. Boeing now says it is working to bring that forward, and a pilot bulletin is being prepared in the meantime so crews know exactly what to expect if VNAV drops out.

None of this puts current MAX 8 or MAX 9 fleets on the ground, and the airlines that responded say their in-service aircraft are not affected. But after the years the MAX spent under a regulatory microscope, any software surprise in a 737 cockpit gets read twice. How quickly Boeing ships the fix, and what the review board decides, will say a lot about how quickly the two newest 737s reach passengers.

The 737 MAX 10, the largest member of the family, on its first flight in June 2021. The software issue could now slow its path to service. Video: Aviation International News

Sources: The Wall Street Journal, CBS News, Bloomberg, AeroTime