MD90 FLT CREW HAS ELECTRICAL FAILURE DURING DEP; DECLARES AN EMER AND DIVERTS FOR LNDG.

Narrative

WE DEPARTED AND WERE CLBING THROUGH 13000 FT MSL WHEN WE EXPERIENCED A LOSS OF BOTH L AND R ELECTRICAL BUSES. THE EMER PWR SYS AUTOMATICALLY PWRED THE EMER BUS; WHICH RESTORED SOME OF THE CAPT'S FLT INSTS; BUT ALL OF MY INSTS WERE DEAD; AND WE LOST CABIN PRESSURIZATION CTL; CAUSING THE CABIN ALT TO BEGIN CLBING. THE CAPT DIRECTED ME TO LEVEL OFF; AND THEN WE QUICKLY COORDINATED A DSCNT TO 10000 FT. WE ELECTED NOT TO DON OUR OXYGEN MASKS SINCE WE WERE AT A SAFE ALT AND DSNDING RAPIDLY BACK DOWN TO 10000 FT; AND WE FELT THAT FLYING THE AIRPLANE AND COORDINATING WITH ATC WERE OUR MOST IMPORTANT IMMEDIATE PRIORITIES. I FLEW 'CROSS-COCKPIT' FOR A FEW MOMENTS WHILE THE CAPT TALKED WITH ATC AND THE CREW; AND THEN HE TOOK THE CTLS AND I BEGAN TO PERFORM THE ABNORMAL CHKLIST PROCS. WE WERE ABLE TO RESTORE ELECTRICAL PWR TO THE L BUS; WHICH ENABLED THE CAPT TO FLY NORMALLY; AND WE PROCEEDED BACK TO ZZZ; DECLARING AN EMER ENRTE. WE FLEW A VISUAL APCH; BUT ON FINAL; WE DISCUSSED THE RWY LENGTH AND OUR ACFT WT; AND DECIDED TO INSTEAD CIRCLE TO THE LONGEST RWY AT ZZZ. WE COMPLETED ALL NORMAL CHKLISTS AND WERE CLRED TO LAND. AFTER PERFORMING AN UNEVENTFUL OVERWT LNDG; WE RETURNED TO THE GATE. AFTER LNDG; I TOOK ANOTHER LOOK AT THE ABNORMAL CHKLIST; AND REALIZED THAT I HAD MISSED A STEP IN THE CHKLIST THAT LIKELY WOULD HAVE ALLOWED US TO RESTORE PWR TO THE R BUS AS WELL; WHICH COULD HAVE BEEN A VITAL STEP AT NIGHT OR IN BAD WX. DISTRS DURING THE RETURN TO ZZZ; AND A CONFUSING CHKLIST FORMAT (THIS IS A FAIRLY INVOLVED PROC; WITH LOTS OF CONDITIONAL BOXED ITEMS THAT REQUIRE THE USER TO SKIP AROUND FROM ONE SECTION TO ANOTHER) CONTRIBUTED TO MY OMITTING A POTENTIALLY IMPORTANT STEP IN THE CHKLIST. I WILL BE ESPECIALLY VIGILANT IN THE FUTURE TO MAKE SURE THAT I DO NOT OVERLOOK ANY STEPS IN ABNORMAL PROCS.