B757-200
Flight Crew Last 90 Days 210; Flight Crew Total 23000; Flight Crew Type 1200
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Maintenance Action; General Declared Emergency
Aircraft
The flight arrived with a write-up on the right engine electric generator. The generator had a history of tripping in flight. The write-up indicated the generator disconnected at the top of descent. Maintenance MEL'd the generator and followed procedures to operate the flight with the APU generator. Included in the procedure was running the right engine on the ground to disconnect the generator and verifying the HMG [hydraulic generator] was operating properly. The flight took off and climbed to cruise normally. Shortly after level off the APU auto-shutdown with a FAULT light and refill showing on the APU [oil] quantity. We followed the APU FAULT procedure and ended up turning off the APU switch. Then we ran the GEN OFF procedure which directed us to land at the nearest suitable airport. We called Dispatch and were told we could go to either airport. They volunteered to coordinate with ATC and operations. We declared an emergency and were given direct routing to the first fix on the ILS. First; (the Captain) flew the airplane while the First Officer and Relief Pilot coordinated with the flight attendants and made announcements to the passengers. The Relief Pilot also used the SATCOM to do some more coordinating with the Dispatcher. We worked through the performance implications of an overweight landing and determined we could land safely. The landing was smooth and the break temperatures never exceeded. Second; emergency trucks followed us to the gate and came on board to make sure everything was OK. We then worked with the ground agents to take care of the passengers. The mechanic found the APU generator had cracked and was leaking oil at a fast rate. After an hour of troubleshooting the flight was cancelled and the passengers and crew deplaned for customs clearance and transportation to hotels. Very good CRM with the cockpit crew; the flight attendants did their jobs well. ATC was terrific giving us the clearances we needed to expedite our arrival. We did have some trouble communicating with dispatch. The Dispatcher seemed confused and was not very helpful. The problem may have been the SATCOM.
B757 Captain reports being dispatched with an inoperative engine driven generator and the APU generator providing the second source of electrical power. After level off the APU shuts down due to oil loss and the flight diverts to the nearest suitable airport.