FAA issued advisory over fuel control switch fault for several Boeing models. Here’s what it said

The US Federal Aviation Administration (FAA) has issued a Special Airworthiness Information Bulletin (SAIB) warning operators of several Boeing aircraft models about potential risks linked to faulty fuel control switches that could trigger unintended in-flight engine shutdowns.

The advisory spans a broad range of aircraft, including the Boeing 717-200, 737 series (covering -700, -800, -900ER, -8, and -9 variants), 747, 757, 767, 787-8/-9/-10, and the MD-11 and MD-90-30 models.

The FAA’s move follows reports from Boeing that some 737 aircraft were delivered with fuel control switches installed without the locking feature engaged. These cockpit switches manage fuel flow to engines and are designed with a safeguard to prevent accidental movement. Without the locking mechanism, the switch can shift between ON and OFF positions without being lifted, raising the chance of an unintended engine shutdown.

“Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown,” the FAA warned.

While the FAA does not currently consider the issue an immediate airworthiness concern under regulations, it is monitoring developments and recommending inspections and, if needed, replacement of affected switches.

The switches in question, manufactured by Honeywell, are identified by part numbers tied to specific aircraft models. For instance, Boeing 737 aircraft with switches labeled P/N 766AT613-3D or 766AT614-3D may lack the improved locking feature. Other affected aircraft include:

• 717-200 (P/N 3TL32-2-3D)
• 747-400 and -400F (P/N 3TL32-3D)
• 757-300 (P/N 3TL32-3D)
• 787-8, -9, -10 (P/N 4TL837-3D)

and additional models listed in the FAA’s detailed table.

The FAA advises airlines to inspect fuel control switches while aircraft are on the ground to confirm proper engagement of the locking mechanism and to replace any faulty units — particularly on the 737 and 737-8/-9 fleets — with upgraded versions featuring improved locks.

Operators are also urged to report any locking mechanism failures to the FAA. For further details, the bulletin lists Tak Kobayashi, an FAA aerospace engineer, as the point of contact.

Although not currently subject to an Airworthiness Directive, the FAA’s recommendations aim to proactively mitigate safety risks associated with potential fuel switch malfunctions across multiple Boeing fleets.