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A trans-pacific B747 flight crew experienced excessive engine four vibrations shortly after takeoff; declared an emergency; dumped fuel and returned to their departure airport.
| Attributes | |
| ACN | 1106505 |
| Time | |
| Date | 201308 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | B747 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Climb |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Turbine Engine |
| Person 1 | |
| Function | First Officer Relief Pilot |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Total 19900 Flight Crew Type 5000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical |
Narrative:
I was the secondary relief pilot on the flight. During [initial] climb; passing 100 AGL; a high vibration was felt in the aircraft and it was evident that it was caused by the number 4 engine. The vibration monitor showed 5.0. Power was reduced on number 4 until the vibration lessened at about 70% N1. We continued the climb as the analysis was made and upon level off after the after T/O check at 3;000 ft the engine limit/surge/stall checklist was accomplished. We declared an emergency aircraft without the need for additional assistance. After conferring with dispatch and maintenance control we agreed the best course of action was to return to our departure airport. We notified the flight attendants and made a PA announcement to inform the passengers of the reason for the return to the field but the landing would be delayed due to the fact that we would need to dump fuel. ATC was notified of the need to dump and we were given holding over rains intersection to do so. Again dispatch was notified with the intended amount of time in the hold. We also requested performance data for the landing. The approach; landing and taxi in to the gate were normal.
Original NASA ASRS Text
Title: A trans-pacific B747 flight crew experienced excessive engine four vibrations shortly after takeoff; declared an emergency; dumped fuel and returned to their departure airport.
Narrative: I was the secondary relief pilot on the flight. During [initial] climb; passing 100 AGL; a high vibration was felt in the aircraft and it was evident that it was caused by the Number 4 engine. The vibration monitor showed 5.0. Power was reduced on Number 4 until the vibration lessened at about 70% N1. We continued the climb as the analysis was made and upon level off after the after T/O check at 3;000 FT the Engine Limit/surge/stall checklist was accomplished. We declared an emergency aircraft without the need for additional assistance. After conferring with Dispatch and Maintenance Control we agreed the best course of action was to return to our departure airport. We notified the flight attendants and made a PA announcement to inform the passengers of the reason for the return to the field but the landing would be delayed due to the fact that we would need to dump fuel. ATC was notified of the need to dump and we were given holding over RAINS intersection to do so. Again Dispatch was notified with the intended amount of time in the hold. We also requested performance data for the landing. The approach; landing and taxi in to the gate were normal.
Data retrieved from NASA's ASRS site as of July 2013 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.