B757 Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Troubleshooting
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem
Aircraft
While enroute in cruise at FL 370; the aircraft displayed a 'DRIVE' discreet caution light for the right engine generator and associated 'R GEN DRIVE' EICAS message. This was not necessarily a 'startle event' to us because we had experienced the same malfunction in the same aircraft on the previous flight to ZZZ1 that morning; and it had an MEL for this flight. At the beginning of the flight; upon pushback; we had to block turn back in when we had an 'L GEN OFF' EICAS message associated with a left engine generator that was cycling on and off. Following the block turn back; we had assisted local maintenance with extensive troubleshooting for the generator(s) which; I believe; resulted in swapping the GCUs (Generator Control Units) between left and right engines to render one generator (the right generator) operable for flight. At cruise; upon recognizing and identifying the 'R GEN DRIVE' malfunction; we ran the appropriate QRH checklist. We then gathered weather information for potential diversion airports in the area and ultimately decided that continuing to ZZZ was our best option for ceiling and visibility conditions. We requested priority handling as a precaution and turned directly to ZZZ. Arrival; approach; and landing were uneventful. We did not find any QRH guidance for the left and right generator off in the electrical non-normal section. While this situation is extremely [un-]likely to occur; it may be worth considering adding guidance for dual generator failure.
Flight dispatched with right engine generator inoperable. After block; left engine generator became intermittent. Flight crew ran QRH and cycled the generator but that was no help. Flight returned to the gate and contacted Dispatch via ACARS.
B757 Captain and both dispatchers who worked the flight reported that after a generator failure was deferred; the other generator failed in cruise.