EASA SIB NM-18-33
Boeing 717, 737, 747, 757, 767, 787, MD-11 and MD-90 Aeroplanes - Fuel Control Switch Locking
Summary
The FAA Special Airworthiness Information Bulletin SAIB: NM-18-33 addresses the potential disengagement of the fuel control switch locking feature on various Boeing aeroplanes including models 717-200, 737 series, 747 series, 757 series, 767 series, 787 series, MD-11, and MD-90-30. The bulletin informs operators about the risk of inadvertent fuel control switch operation due to the locking feature being disengaged, which could lead to unintended engine shutdowns. This information bulletin is advisory and does not mandate regulatory action.
What Changed
This bulletin introduces awareness of a potential issue where the fuel control switch locking feature may be disengaged on affected Boeing aircraft, allowing the switch to move without lifting and increasing the risk of inadvertent operation. It recommends inspection and replacement of switches if the locking feature is found disengaged, and for certain 737 models, it advises replacing the switch with an improved part number that includes a better locking feature.
Why It Matters
This issue is critical for aviation professionals because inadvertent operation of the fuel control switch can cause unintended engine shutdowns, posing safety risks during flight. Operators, maintenance, and compliance teams need to ensure the locking feature is engaged to maintain safe engine control and avoid potential in-flight emergencies. Monitoring and reporting failures help the FAA and Boeing track the issue and improve safety measures.
What To Do
Operators of affected Boeing aircraft should inspect the fuel control switch locking feature at the earliest opportunity while the aircraft is on the ground. If the switch moves without lifting, it must be replaced promptly. Specifically, Boeing 737-700, -700C, -800, -900ER, and 737-8 and -9 models with part number 766AT613-3D should replace the switch with part number 766AT614-3D, which has an improved locking feature. Operators are also encouraged to report any locking feature failures to Boeing with detailed information.