FAA Reviews Boeing 737 MAX Software Issue After Airlines
The FAA is reviewing a flight management computer software glitch on some Boeing 737 MAX jets, convening a safety board.
The U.S. Federal Aviation Administration is reviewing a potential issue in updated flight management computer software on some Boeing 737 MAX aircraft. Southwest Airlines and United Airlines have told Boeing they will not accept new 737 MAX jets equipped with the affected software versions 14 or 14.1.
The FAA said it is aware of the potential issue and is working closely with Boeing and airlines. It will convene a Corrective Action Review Board to examine Boeing's safety findings and proposed solution. This CARB process is the agency's standard method for determining whether an issue represents a safety concern and what corrective measures may be appropriate.
Software versions 14 and 14.1 linked to vertical navigation disengagement
The glitch surfaced in FMC software versions 14 and 14.1. The problem can cause automated vertical navigation to disengage during a specific missed-approach scenario. This condition can arise in rare cases when a crew is flying a precision approach with the autopilot engaged, initiates a missed approach or go-around, and then changes the preprogrammed flight plan.
In that situation, the flight guidance system may incorrectly transition out of vertical navigation to a simpler pitch mode such as level change or vertical speed. VNAV follows the vertical profile the FMC computes from the flight plan's altitude and speed constraints. Level change holds a target airspeed while the autothrottle sets climb or idle thrust, and vertical speed holds a rate of climb or descent the pilot selects. Neither mode follows the FMC's vertical path, so crews must manage those constraints themselves.
The scenario would typically occur close to the airport, where crew workload is already high. Boeing said the autopilot continues to function if VNAV disengages and that pilots are trained to land without it. Alaska Airlines, American Airlines, Southwest Airlines, and United Airlines each stated that none of their in-service 737 MAX aircraft use the affected software. Those statements cover four U.S. Carriers and concern aircraft already in service.
Boeing downplays safety risk while preparing software fix for 2028
Boeing reviewed the condition and concluded in February 2025 that it did not constitute a safety issue. The company received additional information from operators earlier this year, which prompted it to launch a formal safety review board. Boeing told operators in a bulletin in late August that the glitch is not an immediate safety issue.
A Boeing spokesperson said the company informed all 737 operators last month about a software issue where pilots may not have access to automated flight guidance during a specific landing scenario. The company shared information with operators that reinforced existing pilot procedures for safely handling such cases. Boeing's initial bulletin also said updated pilot guidance would follow in November, and the company is working to bring both forward.
Boeing anticipates the next software update in 2028 and is working to accelerate that timeline based on operator feedback. The company's engineers are working on a software update to permanently address the issue. Boeing informed the FAA of the issue as part of its safety review process and is working under the agency's oversight to complete the software update.
Southwest and United refuse new deliveries; impacts MAX 7 and MAX 10 certification
Southwest Airlines and United Airlines told Boeing they will not accept new 737 MAX aircraft equipped with the affected software. For new deliveries, the airlines said they would not accept aircraft with the affected software and would take aircraft with a previous version instead. Southwest stated that none of its fleet is equipped with Version U.14, including new deliveries of MAX 8 airplanes.
An airline first told Boeing about the condition in November 2024. The 737 MAX 7 was certified with software version 14. The FAA certified the 737 MAX 7 on August 3 after a development and certification program that lasted almost a decade. Southwest accounts for nearly all of the MAX 7's current order book and had been expected to begin receiving the type later this year. It is not yet clear whether the MAX 7 can be delivered with an earlier software version.
The larger 737 MAX 10 used version 14.1 during certification flight testing. Boeing completed its final planned certification flight for the 737 MAX 10 in July. On September 16, CEO Kelly Ortberg said MAX 10 certification would arrive very soon. Alaska Airlines has 105 MAX 10s on order, with options for another 35, and had expected FAA certification by the end of September. The FAA has not said whether the CARB review must be completed before the MAX 10 can be certified.
Boeing told Airways it did not have specific aircraft figures to share. It remains unclear how many undelivered aircraft carry versions 14 or 14.1, or whether any operator outside the U.S. Already flies with them. The formal review began in September. The board's findings went to the FAA this month and will be reviewed by the CARB. The FAA will convene a Corrective Action Review Board to examine Boeing's safety findings and proposed solution for the FMC software issue.
