FAA Issues Service Bulletin for Boeing 737 NG and MAX VNAV Disconnect Issue

The Federal Aviation Administration (FAA) has issued a Service Bulletin to address an issue with Boeing's 737 NG and MAX aircraft. The bulletin, SAIB 2026-17, is dated October 3, 2026, and affects aircraft equipped with Flight Management Computer software U14.0 or U14.1.

The problem occurs when the crew navigates directly to a waypoint outside of an airport's approach procedures after a go-around, causing the vertical navigation mode (VNAV) to disconnect. This can result in the autopilot switching to a simpler level of pitch-control automation, requiring additional procedural steps for pilots to re-engage VNAV.

Boeing and GE Aerospace are working on a permanent patch to resolve the issue, while Boeing is formalizing procedures with airlines to reactivate VNAV if the scenario occurs. The FAA notes that the recommendations in the bulletin are not mandatory, but rather provide guidance for operators.