The FAA is examining a software flaw in some Boeing 737 Max aircraft that could remove a layer of automated guidance during one of the most demanding phases of flight. Boeing describes the problem as manageable, but airline decisions suggest confidence in the fix remains limited.

The glitch can emerge after a missed approach when pilots modify a preprogrammed flight path while using autopilot. In that situation, the aircraft’s vertical navigation system, or VNAV, may disengage, forcing crews to take additional steps during a subsequent approach. The scenario is especially sensitive because it can occur at low altitude, when cockpit workload is already high. “Are you introducing distractions at the worst possible moment?” an airline source told CBS News.¹

Boeing has emphasized that autopilot would continue functioning and that pilots are trained to land without VNAV. The company said it had reinforced existing procedures with operators and was developing a permanent software update. It has also said the issue is not an immediate safety concern.

The FAA’s position is more conditional. The agency said it was working with Boeing and airlines and “will take immediate action if it identifies a safety concern.”² That review could affect certification of the delayed Max 10 and deliveries of the Max 7, both of which are tied to the newer software versions.

Airlines, meanwhile, are taking a risk-control approach rather than waiting for the investigation to conclude. Southwest and United said they would not accept aircraft equipped with the affected software, while Southwest said none of its fleet uses Version U.14. The carriers’ response contrasts with Boeing’s assurance that existing training is sufficient—and reflects the industry’s lingering sensitivity after two fatal Max crashes and later manufacturing failures.