Boeing has found a software issue in 737 MAX aircraft that, in certain scenarios, could disable automatic navigation function during landing. The issue occurs after a missed approach when pilots change the preset route for the next landing attempt.
In these circumstances, the crew may have to continue the flight manually, without some of the autopilot and automatic vertical navigation functions. The problem is related to a software update in the cockpit. According to information cited by the Wall Street Journal, it is not known how many aircraft in service are equipped with the affected version.
Boeing notified airlines of the problem in late August. The company initially deemed it not a safety risk because pilots are trained to land without the automated features. However, after additional input from operators, the manufacturer began a formal review in September.
FAA is investigating the case
The U.S. Federal Aviation Administration is investigating the issue and reviewing Boeing's proposed solution. The agency said it would take immediate action if it determines a safety threat.
Boeing is working with airlines on a temporary procedure that would allow pilots to restore automatic vertical navigation if the feature is interrupted. "We are working directly with airlines to develop a procedure that will allow pilots to re-enable automatic vertical navigation in such a scenario," the company said.
Southwest Airlines and United Airlines have requested that their new 737 MAX aircraft not be shipped with the affected software, but with an earlier version. Boeing is developing a permanent fix, initially expecting it to be ready in early 2028.
Possible implications for new models
The incident could also affect the certification of the Boeing 737 MAX 10, as well as the introduction of the MAX 7. According to Yonhap, 2,422 MAX 8 and MAX 9 aircraft are in operation worldwide, but the number of machines with the affected software version is still being specified.
The problem is different from the defects in the MCAS system associated with the two fatal crashes of the 737 MAX in 2018 and 2019. In this case, it is an automated navigation function during landing, and Boeing has not reported any accidents caused by the new software problem.
Sources: Wall Street Journal, Investing, Yonhap