FAA Reviews Boeing 737 MAX Software Glitch Affecting Some Approaches

Boeing has identified a flight-computer software issue on some 737 MAX aircraft that can disrupt automated vertical navigation after a missed approach when pilots alter a preprogrammed flight path. The Federal Aviation Administration said it is reviewing the problem and Boeing’s proposed fix and will act immediately if it identifies a safety concern.

The issue can occur when pilots are conducting a precision approach with the autopilot engaged and modify a preprogrammed flight path after aborting a landing. The aircraft’s vertical navigation system, known as VNAV, may disengage and shift to a less sophisticated form of automated pitch control. Boeing said the autopilot continues to operate and pilots are trained to land without VNAV, though additional steps may be required on a subsequent approach.

Boeing notified all 737 operators last month, reinforced existing procedures for handling the scenario and said its engineers are developing a permanent software update. CBS News reported that the glitch affects versions 14 and 14.1 of the MAX flight-management computer operating system.

Alaska Airlines, American Airlines, Southwest Airlines and United Airlines told CBS News that their in-service MAX fleets do not use the affected versions. Southwest and United have also said they will not accept new aircraft equipped with the software, opting for an earlier version instead.

The FAA plans to convene a Corrective Action Review Board. The review comes as Boeing seeks certification of the 737 MAX 10; the MAX 7 was certified in early August with the newest software installed.