Narrative:

We were cruising at FL300. We started experiencing uncommanded changes to our FMA's (flight mode annunciators) followed by flickering du's (display units). Shortly thereafter our master cautions lit up and numerous alerts were displayed at one time (19). Obviously we had a major electrical malfunction. Both the captain's and first officer's nav displays lost map information and the captain's FMC locked up. Selecting various synoptic displays revealed many 'X'ed out symbols.we used the QRH to address some level 2 alerts; but this was no help. We notified ATC that we were unsure of our navigation capability and requested radar vectors while we tried to pinpoint the problem. We also began requesting possible alternate airports that had good weather nearby. Since I was not sure of the extent of damage to the electrical system. I began to fear some of the worst case scenarios (loss of all du's; electrical smoke; fumes; fire; etc). Due to its close proximity; good weather and facilities; I made the decision to divert to ZZZ. ATC was very accommodating and immediately honored my request for descent and radar vectors and an emergency was declared. We were told to expect a visual approach. I requested about a 20 mile final in order to have sufficient time to insure the aircraft could be properly configured for landing. The aircraft did configure normally and we touched down smoothly following the visual approach. The landing weight was slightly above maximum (approximately 1300 lbs). Fire trucks on the scene did not notice anything unusual externally and we proceeded to the terminal ramp for parking. Initially we had no idea what caused such a major malfunction. Mechanics were flown in later that night to work on the aircraft. We reported the next morning to ferry the aircraft; and met with the mechanics. They told us that they replaced the left pcdu (power conversion distribution units) and the epcu (electrical power control unit). That seemed to explain why we couldn't determine exactly what we had lost; since there is no alert or QRH procedure for a pcdu failure.

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Original NASA ASRS Text

Title: Confronted with multiple electrical anomalies for which there were no ameliorative checklists; a B717 flight Crew declared an emergency and diverted to a nearby airport.

Narrative: We were cruising at FL300. We started experiencing uncommanded changes to our FMA's (Flight Mode Annunciators) followed by flickering DU's (Display Units). Shortly thereafter our master cautions lit up and numerous alerts were displayed at one time (19). Obviously we had a major electrical malfunction. Both the Captain's and First Officer's Nav displays lost map information and the Captain's FMC locked up. Selecting various synoptic displays revealed many 'X'ed out symbols.We used the QRH to address some level 2 alerts; but this was no help. We notified ATC that we were unsure of our navigation capability and requested radar vectors while we tried to pinpoint the problem. We also began requesting possible alternate airports that had good weather nearby. Since I was not sure of the extent of damage to the electrical system. I began to fear some of the worst case scenarios (loss of all DU's; electrical smoke; fumes; fire; etc). Due to its close proximity; good weather and facilities; I made the decision to divert to ZZZ. ATC was very accommodating and immediately honored my request for descent and radar vectors and an emergency was declared. We were told to expect a visual approach. I requested about a 20 mile final in order to have sufficient time to insure the aircraft could be properly configured for landing. The aircraft did configure normally and we touched down smoothly following the visual approach. The landing weight was slightly above maximum (approximately 1300 lbs). Fire trucks on the scene did not notice anything unusual externally and we proceeded to the terminal ramp for parking. Initially we had no idea what caused such a major malfunction. Mechanics were flown in later that night to work on the aircraft. We reported the next morning to ferry the aircraft; and met with the mechanics. They told us that they replaced the left PCDU (Power Conversion Distribution Units) and the EPCU (Electrical Power Control Unit). That seemed to explain why we couldn't determine exactly what we had lost; since there is no alert or QRH procedure for a PCDU failure.

Data retrieved from NASA's ASRS site as of April 2012 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.