Boeing 747-400 and 747-8 Aeroplanes - Flight Management Computing Software System
- Published
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of Boeing 747-400 and 747-8 airplanes with FMC software BP 4.0 should review Boeing Fleet Team Digest 747-FTD-34-19008 and implement any interim actions recommended therein as soon as possible. They should also monitor further FAA rulemaking and Boeing communications for updates and corrective measures.
Summary
The Special Airworthiness Information Bulletin FAA SAIB: AIR-20-18 provides information regarding flight management computer (FMC) software issues affecting Boeing 747-400 and 747-8 series airplanes equipped with FMC software block point 4.0. It addresses reports of dual FMC failures and resets occurring primarily during approach operations, which increase pilot workload and affect flight management functions.
What changed
This bulletin introduces awareness of dual FMC resets and failures linked to the NGFMC BP 4.0 software update on Boeing 747-400 and 747-8 airplanes. It highlights ongoing investigations by Boeing and its supplier into these anomalies and anticipates future rulemaking to resolve issues related to FMC software block points 3.1 and 4.0.
Why it matters
The FMC failures can cause cold starts of both FMCs, auto throttle disconnects, loss of LNAV and VNAV modes, and deactivation of the flight plan, requiring flight crews to re-enter critical performance initialization data during high workload phases such as approach. This impacts operational safety and increases pilot workload, making it essential for operators and maintenance teams to be aware and prepared.
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