Boeing looked close to certifying its biggest 737. Then a software problem got in the way.

On Monday, 28 September, FAA Administrator Bryan Bedford said the agency would hold off on certifying the 737 MAX 10 until it understands a newly disclosed glitch in the jet's flight guidance software. Boeing shares fell 6.9 percent on the news. Nobody at the FAA would say how long the pause will last.

What the FAA Said

Bedford did not dress it up. Until the FAA is satisfied, the MAX 10 waits.

He added that a fix might come relatively quickly, but that it could take days, weeks or months. The FAA will convene a Corrective Action Review Board to decide whether the software poses an unreasonable safety risk. According to Reuters, that process is unlikely to begin before next week.

The Glitch

Boeing disclosed the problem on 26 September. It said the software could prevent pilots from accessing automated flight guidance during a specific landing scenario. The FAA says the issue shows up during a go-around, the moment when the crew abandons a landing and climbs away for another try. The pilots keep full control of the aircraft, but lose part of the automation that normally helps them fly the climb-out, so their workload rises at the busiest point of the approach.

We covered the details of the fault, which affects the vertical navigation (VNAV) function, on 27 September. What is new is the cost: on Monday the problem reached the MAX 10's certification.

Who Is Affected

The fault is not limited to the MAX 10. According to AeroTime, WestJet already operates MAX jets with the affected software. The Canadian airline says it has had no in-service issues, does not see the matter as a safety concern, and has procedures in place to handle such an event.

United Airlines, the largest MAX 10 customer, says none of its current aircraft use the affected software, and it is refusing deliveries of aircraft that do. Alaska Airlines says the same about its fleet and expects its first MAX 10 in spring 2027.

So Close, Again

The timing stings. The FAA certified the smaller MAX 7 on 3 August 2026, after years of delay. On 16 September, Boeing chief executive Kelly Ortberg said MAX 10 certification would come very soon, and on 24 September Alaska's chief operating officer expected it by the end of the month. Reuters says the industry was looking at October.

Now the stretched 737 is waiting again. For airlines that have been promised the MAX 10 for years, one more wait is not a crisis. For Boeing, which needs every certified variant it can deliver, it is another week in which the FAA sets the pace.

Sources: Reuters, AeroTime, CBS News, FlightGlobal