The Federal Aviation Administration is investigating a software flaw in some Boeing 737 Max aircraft that could cause an automated flight guidance system to disengage during an aborted landing, commonly known as a “go-around.” In rare circumstances where there is a missed approach (and where a pilot uses a precision approach with the autopilot engaged and makes changes to his pre-programmed flight plan), a problem with the flight management computer could cause the aircraft’s vertical navigation system, known as VNAV, to disengage and transition to a less sophisticated level of automated pitch control. VNAV is essentially designed to automatically maintain preplanned altitude at various points along a flight path. However, if this problem occurs, pilots will need to take additional measures during their subsequent approach. The scenario would typically occur in an environment adjacent to a low-altitude airport where pilots already have a heavy workload. “How busy do you want your team to be?” An airline source told CBS News about the issue. “Are they introducing distractions at the worst possible time?” “Last month, we informed all 737 operators of a software issue where pilots may not have access to automated flight guidance during a specific landing scenario,” a Boeing spokesperson told CBS News in a statement. “We shared information with operators that reinforced existing pilot procedures to safely handle such cases. Our engineers are working on a software update to permanently address the issue.” The Boeing spokesperson said that even if VNAV is disconnected, the autopilot will continue to operate, adding that all pilots are trained to land safely without VNAV. In a bulletin sent to airlines late last month, Boeing told operators that the problem is not an immediate safety issue. It appeared in versions 14 and 14.1 of the Max’s flight management computer operating system. “The FAA is aware of a potential issue in a software update for the flight computers on certain Boeing 737 MAX aircraft and is working closely with Boeing and the airlines,” the FAA told CBS News in a statement. “The FAA will convene a Corrective Action Review Board (CARB) and take immediate action if it identifies a safety issue.” Southwest Airlines and United Airlines have informed Boeing that they will not accept delivery of new aircraft with that operating system, but will instead opt for an older version. Alaska Airlines, American Airlines, Southwest and United told CBS News that none of their 737 Max fleets in service use the software version in question. CBS News has learned that an airline first reported the issue to Boeing in November 2024. The company reviewed it and determined in February 2025 that it was not a safety issue. However, Boeing received what one source described as “additional information from operators” earlier this year, prompting the manufacturer to create a formal safety review board. The board’s findings were sent to the FAA this month and will be reviewed by CARB. Boeing’s initial bulletin told airlines that a software fix would be ready sometime in 2028 and that it would issue updated guidance on procedures for pilots to follow in November. The company is working to accelerate both efforts. The FAA review could further delay certification of the 737 Max 10, the fourth and largest variant of the Max. The Max 10 was thought to be days away from FAA certification, but years behind schedule. The issue could also delay deliveries of the newly certified 737 Max 7. Almost the entire order book for that plane will go to Southwest. The Max is a cash cow for Boeing and is vital to its recovery efforts. The plane has been the subject of two high-profile crashes in 2018 and 2019 that killed 346 people due to faulty software, and experienced a mid-flight door panel explosion on an Alaska Airlines flight in January 2024 that was blamed on manufacturing errors. Of note, several US airlines appear to be taking a trust-but-verify approach with Boeing on this issue, after being hit by grounding and delays due to Boeing’s previous mistakes on the Max. The Max 7 was certified with software version 14, while the Max 10 used version 14.1 during its certification testing. Southwest was scheduled to begin taking Max 7 deliveries this fall. It is unclear whether the airline will accept delivery at this time, while Alaska Airlines is assumed to be the launch customer for the Max 10. The software issue was first reported by the Wall Street Journal. CBS News also contacted Allegiant Air, which also operates the 737 Max, for comment. More from CBS News Go deeper with The Free Press in:
