Boeing 737 MAX Software Glitch Discovered in VNAV Function

A software glitch has been discovered in the Boeing 737 MAX flight management system, specifically affecting the vertical navigation (VNAV) function. According to reports, during a precision approach flown on autopilot followed by a go-around and then a change in pre-programmed flight path, VNAV can disengage, causing the autopilot to switch to a simpler pitch mode.

The glitch affects versions 14 and 14.1 of the software used in the 737 MAX 7 and 737 MAX 10 models. Boeing confirmed the issue and stated that existing pilot procedures can manage the situation safely, but the FAA is convening a Corrective Action Review Board to decide whether it's a safety concern.

The timeline for addressing this issue is notable, as an airline first reported the behaviour to Boeing in November 2024, with Boeing concluding it wasn't a safety concern. However, further operator information led to a formal safety review and notification of the FAA in September 2026.