A B767'S R GEN TRIPPED AND WOULD NOT RESET AT FL370. THE CREW DSNDED TO FL270 WHERE THE APU STARTED. THE FLT CONTINUED TO ITS DEST.

Narrative

IN CRUISE AT FL370; THE R ENG DRIVEN GENERATOR DROPPED OFF LINE; AND BECAUSE OF THAT BOTH UTILITY BUSSES SHED ALSO. IMMEDIATELY INITIATED THE APU START; AND THEN WENT TO THE QRH AND WENT THROUGH THE GENERATOR OFF PROC. THE RESET OF THE R GENERATOR RESULTED IN THE ILLUMINATION OF THE R GENERATOR DRIVE LIGHT ON THE OVERHEAD PANEL. THE APU DID NOT START. BECAUSE WE HAD ONLY 1 ELECTRICAL PWR SOURCE; DECLARED AN EMER AND WE INITIATED A DSCNT IN PREPARATION FOR A DIVERSION AND ALSO BECAUSE WE THOUGHT THAT ANOTHER APU START ATTEMPT AT A LOWER ALT WOULD BE SUCCESSFUL. THE APU DID START WHEN WE WERE BELOW 30000 FT. AT THAT POINT; WE COULD SEE NO REASON NOT TO CONTINUE ON TO ZZZ NOW THAT WE HAD 2 GOOD GENERATORS. WE CANCELED OUR EMER WITH ATC AND RESUMED OUR NORMAL ALT AND RTE TO ZZZ ALSO SPOKE WITH DISPATCH AND THEY AGREED WITH OUR DECISION TO PRESS ON. SUPPLEMENTAL INFO FROM ACN 804602: REQUESTED LOWER TO ATTEMPT APU START AT LOWER ALT AND BEGAN LOOKING FOR VFR ALTERNATE. APU STARTED AT FL270.