Preparations for the Boeing 737 MAX 7’s entry into service and the completion of certification for the larger MAX 10 have encountered another obstacle. The US Federal Aviation Administration (FAA) is reviewing a flight management computer software issue that, under certain circumstances following a missed approach, can cause the loss of automated vertical navigation. Boeing is developing a software fix, while any potential impact on certification and delivery schedules remains unconfirmed, AeroTime reports.

The issue has already influenced decisions by some customers. According to Air Data News, Southwest Airlines and United Airlines have decided not to accept new aircraft equipped with the affected software versions, opting instead for an earlier release. Alaska Airlines, American Airlines, Southwest and United said their MAX aircraft currently in service do not use the affected versions, 14 and 14.1. However, this does not provide a complete picture of their use across the global fleet.

As AeroTime explains, the problem can arise during a specific sequence of events: the crew conducts a precision approach with the autopilot engaged, initiates a go-around and subsequently modifies the pre-programmed flight path. Under these circumstances, VNAV, the function that automatically follows the vertical flight profile and programmed altitude constraints, may become unavailable.

Boeing notes that losing VNAV does not necessarily mean the autopilot will disengage. The aircraft can continue flying with a simpler mode of automated pitch control, but the crew must take additional steps to manage the vertical flight path and prepare for the next approach. The operational significance lies in when the issue may occur: during a missed approach, pilots are already managing the aircraft’s configuration, monitoring its flight path and communicating with air traffic control.

The manufacturer has told operators that existing pilot procedures allow crews to manage the situation safely. However, the FAA will conduct its own assessment through a Corrective Action Review Board, known as CARB. The regulator has said it will take immediate action if it identifies a safety concern.

For the two newest members of the 737 MAX family, the review comes at different stages of their development. The MAX 7 is already certified: on August 3, 2026, the FAA issued an amended type certificate following almost a decade of reviews. The agency said the approval followed changes to flight control software, flightcrew alerting and the engine anti-ice system. The latter modification is intended to prevent the engine inlet from overheating and potentially weakening the surrounding structure.

For the MAX 10, the outstanding question is whether the review of the newly identified software issue will affect the remaining steps towards certification. According to Air Data News, the MAX 7 was certified with software version 14, while the MAX 10 used version 14.1 during certification testing. Both versions are covered by the current review.

A distinction should also be made between the start of deliveries and the launch of commercial flights. On September 16, Reuters reported comments from Southwest Chief Financial Officer Tom Doxey indicating that initial MAX 7 deliveries were expected around the end of 2026, with entry into service planned for early 2027. The latest review therefore raises questions about the configuration in which aircraft will be delivered and any additional measures required before passenger operations begin. No changes to those timelines resulting from this issue have been confirmed so far.