Flight Crew Air Transport Pilot (ATP)
Flight Crew Total 19900; Flight Crew Type 5000
Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport; Flight Crew Returned To Gate; General Declared Emergency
Aircraft
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.
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.