B747 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 90; Flight Crew Total 22000; Flight Crew Type 110
Aircraft Equipment Problem Critical; Inflight Event / Encounter Bird / Animal
Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency
Aircraft; Environment - Non Weather Related
After liftoff we felt a strong vibration from the Number 4 Engine. The N1 vibration indicated above 5. At approximately 2;000 FT we retarded engine per the QRH. Vibration went away but continued once throttle moved above 70% N1. We left Number 4 Engine retarded and climbed to FL220 where with concurrence from Dispatch and Maintenance Control declared an emergency; dumped fuel and returned to our departure airport. After a normal landing and gate return; Maintenance advised us that there was a bird strike on the Number 4 engine.
We coordinated with ATC to dump fuel down to Max Landing Weight. Approximately 220;000 LBS of fuel was dumped while holding over the intersection.
Upon experiencing excessive vibration from the Number 4 Engine shortly after takeoff; a B747 flight crew declared an emergency; shut down the engine; dumped fuel to max landing weight and returned safely to their departure airport.