Narrative:

While climbing through FL190 in rain, light to moderate turbulence and light icing with autoplt and automatic throttles engaged, generators relays began to cycle open and closed with as many as 9 overhead annunciator messages being displayed intermittently. After approximately 10-15 seconds the situation stabilized with left generator failure indicated. Autoplt and automatic throttles had disengaged, both maps displayed failure, FMS route and deactivated, and captain's ADI had failed to a blank screen. Captain transferred control of aircraft to first officer as he had an operable ADI. About this time, the altitude alert sounded. Altimeter indicated 21400 -- altitude select window showed 21000. Both first officer and I thought our clearance was to FL230. I immediately called ZTL to verify our altitude clearance while the first officer descended to FL210. ZTL responded we were now cleared to FL270. The first officer resumed a climb to FL270. We then accomplished the abnormal procedure and reinstated the autoplt, automatic throttles and reloaded the FMS data. We could not restore the left generator to power the left AC bus even though volts (and) frequency were normal after a reset. APU was started and placed on the left AC bus. Flight then continued to destination normally. Crew allowed electrical fault to distract us from primary duty of flying the aircraft. I am still uncertain if electrical relays cycling changed digital display of the altitude select window from 23000 or if we were both incorrect in thinking our clearance was to FL230.

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Original NASA ASRS Text

Title: ACR LGT TYPE ACFT OVERSHOT CLB CLRNC ALT DURING AN ACFT ELECTRICAL PROBLEM.

Narrative: WHILE CLBING THROUGH FL190 IN RAIN, LIGHT TO MODERATE TURB AND LIGHT ICING WITH AUTOPLT AND AUTO THROTTLES ENGAGED, GENERATORS RELAYS BEGAN TO CYCLE OPEN AND CLOSED WITH AS MANY AS 9 OVERHEAD ANNUNCIATOR MESSAGES BEING DISPLAYED INTERMITTENTLY. AFTER APPROX 10-15 SECONDS THE SITUATION STABILIZED WITH L GENERATOR FAILURE INDICATED. AUTOPLT AND AUTO THROTTLES HAD DISENGAGED, BOTH MAPS DISPLAYED FAILURE, FMS RTE AND DEACTIVATED, AND CAPT'S ADI HAD FAILED TO A BLANK SCREEN. CAPT TRANSFERRED CTL OF ACFT TO FO AS HE HAD AN OPERABLE ADI. ABOUT THIS TIME, THE ALT ALERT SOUNDED. ALTIMETER INDICATED 21400 -- ALT SELECT WINDOW SHOWED 21000. BOTH FO AND I THOUGHT OUR CLRNC WAS TO FL230. I IMMEDIATELY CALLED ZTL TO VERIFY OUR ALT CLRNC WHILE THE FO DSNDED TO FL210. ZTL RESPONDED WE WERE NOW CLRED TO FL270. THE FO RESUMED A CLB TO FL270. WE THEN ACCOMPLISHED THE ABNORMAL PROC AND REINSTATED THE AUTOPLT, AUTO THROTTLES AND RELOADED THE FMS DATA. WE COULD NOT RESTORE THE L GENERATOR TO PWR THE L AC BUS EVEN THOUGH VOLTS (AND) FREQ WERE NORMAL AFTER A RESET. APU WAS STARTED AND PLACED ON THE L AC BUS. FLT THEN CONTINUED TO DEST NORMALLY. CREW ALLOWED ELECTRICAL FAULT TO DISTRACT US FROM PRIMARY DUTY OF FLYING THE ACFT. I AM STILL UNCERTAIN IF ELECTRICAL RELAYS CYCLING CHANGED DIGITAL DISPLAY OF THE ALT SELECT WINDOW FROM 23000 OR IF WE WERE BOTH INCORRECT IN THINKING OUR CLRNC WAS TO FL230.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.