Narrative:

Lost all aircraft power during cruise. Aircraft panel appeared normal. Battery discharge light came on. Hmg did not activate as it should have. Declared emergency and landed at ZZZZ. Landing and roll out both normal. Fsi conducted 4-WED-04 via conference call while in ZZZZ. Callback conversation with reporter revealed the following information: the reporter stated the airplane was operated for 41 mins on the battery until the airplane was on the ground and only a few lights were operative, battery discharge light, anti-skid warning and EICAS. The reporter said the problem was traced to a grounding bracket located in the electrical and electronics compartment and was the common ground for the airplane. The reporter said the bracket was found riveted to structure with both surfaces painted. The reporter stated the airplane had a previous maintenance history of utility bus failures. The reporter stated the battery was powering the airplane for 41 mins, 11 more mins than the manual states. The reporter said if this incident occurred over water, it would have been necessary to ditch. The reporter stated the hydraulic motor generator did not operate with the loss of left and right AC busses. The reporter said the carrier has checked all the fleet grounding brackets for paint on paint surfaces and security.

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Original NASA ASRS Text

Title: A B767-300 IN CRUISE AT FL310 DECLARED AN EMER AND DIVERTED DUE TO LOSS OF ALL ELECTRICAL POWER. MAIN SHIP'S BATTERY ONLY POWER AVAILABLE.

Narrative: LOST ALL ACFT POWER DURING CRUISE. ACFT PANEL APPEARED NORMAL. BATTERY DISCHARGE LIGHT CAME ON. HMG DID NOT ACTIVATE AS IT SHOULD HAVE. DECLARED EMER AND LANDED AT ZZZZ. LANDING AND ROLL OUT BOTH NORMAL. FSI CONDUCTED 4-WED-04 VIA CONFERENCE CALL WHILE IN ZZZZ. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE WAS OPERATED FOR 41 MINS ON THE BATTERY UNTIL THE AIRPLANE WAS ON THE GND AND ONLY A FEW LIGHTS WERE OPERATIVE, BATTERY DISCHARGE LIGHT, ANTI-SKID WARNING AND EICAS. THE RPTR SAID THE PROB WAS TRACED TO A GROUNDING BRACKET LOCATED IN THE ELECTRICAL AND ELECTRONICS COMPARTMENT AND WAS THE COMMON GND FOR THE AIRPLANE. THE RPTR SAID THE BRACKET WAS FOUND RIVETED TO STRUCTURE WITH BOTH SURFACES PAINTED. THE RPTR STATED THE AIRPLANE HAD A PREVIOUS MAINT HISTORY OF UTILITY BUS FAILURES. THE RPTR STATED THE BATTERY WAS POWERING THE AIRPLANE FOR 41 MINS, 11 MORE MINS THAN THE MANUAL STATES. THE RPTR SAID IF THIS INCIDENT OCCURRED OVER WATER, IT WOULD HAVE BEEN NECESSARY TO DITCH. THE RPTR STATED THE HYDRAULIC MOTOR GENERATOR DID NOT OPERATE WITH THE LOSS OF L AND R AC BUSSES. THE RPTR SAID THE CARRIER HAS CHECKED ALL THE FLEET GROUNDING BRACKETS FOR PAINT ON PAINT SURFACES AND SECURITY.

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.