EASA SIB NM-20-11
Boeing 777 Airplanes - Autopilot System - Uncommanded Autothrottle Advancement
Summary
The FAA Special Airworthiness Information Bulletin SAIB: NM-20-11 is an informational bulletin addressing the potential for uncommanded autothrottle advancement on Boeing 777 airplanes during ground operations. It highlights reports of unexpected throttle advancement caused by a short circuit in the takeoff/go-around switch wiring. The bulletin provides background on the issue and references Boeing service and operational guidance to mitigate the risk.
What Changed
This bulletin introduces awareness of the uncommanded autothrottle advancement issue on Boeing 777 airplanes and references Boeing Service Bulletin 777-22-0038 and Flight Crew Operations Manual Bulletin TBC-142 R2. It does not mandate regulatory action but recommends implementing Boeing's wiring modification and operational procedures to prevent unintended thrust lever movement.
Why It Matters
This information is important for aviation professionals because uncommanded autothrottle advancement during ground operations can pose safety risks and operational disruptions. Operators and maintenance teams need to understand the root cause and apply Boeing's recommended modifications and procedures to maintain safe aircraft operation and avoid unexpected thrust changes.
What To Do
Owners and operators of Boeing 777 airplanes are advised to incorporate the wiring changes described in Boeing Service Bulletin 777-22-0038 and follow the operational guidance in Flight Crew Operations Manual Bulletin TBC-142 R2 at the earliest opportunity. There is no mandatory compliance deadline, but timely action is recommended to mitigate the risk.