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B747-400 first officer reported an AC electrical system malfunction which resulted in a return to the departure airport.
| Attributes | |
| ACN | 1675534 |
| Time | |
| Date | 201908 |
| Place | |
| Locale Reference | ZZZZ.ARTCC |
| State Reference | FO |
| Aircraft 1 | |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Component | |
| Aircraft Component | AC Generation |
| Person 1 | |
| Function | First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe |
Narrative:
At about one hour into our flight; I had begun my rest in the bunk when I heard a bang similar to someone dropping something in the cockpit additionally the light in the crew rest momentarily went out and back on. The captain alerted me; and I return to the cockpit to find numerous EICAS messages. The other first officer [first officer] was flying without autopilot or auto throttle. The captain and I evaluated the messages and began to work the QRH for those messages. We discovered that the AC number 3 and number 4 dist circuit breaker (35 amp) had tripped we did not reset. After completion of the QRH items we made the decision to return to ZZZZ. The other first officer and I swap seats and I resumed duties as pilot flying. The flight was then vectored to a holding point to dump fuel to achieve our landing weight. We landed at ZZZZ without further incident. Crew executed good CRM and no recommendations could prevent in the future.
Original NASA ASRS Text
Title: B747-400 First Officer reported an AC electrical system malfunction which resulted in a return to the departure airport.
Narrative: At about one hour into our flight; I had begun my rest in the bunk when I heard a bang similar to someone dropping something in the cockpit additionally the light in the crew rest momentarily went out and back on. The Captain alerted me; and I return to the cockpit to find numerous EICAS messages. The other FO [First Officer] was flying without autopilot or auto throttle. The Captain and I evaluated the messages and began to work the QRH for those messages. We discovered that the AC Number 3 and Number 4 DIST circuit breaker (35 amp) had tripped we did not reset. After completion of the QRH items we made the decision to return to ZZZZ. The other FO and I swap seats and I resumed duties as pilot flying. The flight was then vectored to a holding point to dump fuel to achieve our landing weight. We landed at ZZZZ without further incident. Crew executed good CRM and no recommendations could prevent in the future.
Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.