They have ruled out two possibilities -- mechanical "impact" damage, like that caused by being dropped, or short-circuiting outside the battery.

CNN: Boeing can conduct Dreamliner test flights

During the storm, water filled the basement of the Immigration Building, and there was also significant damage to mechanical systems and the building's fire suppression system.

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Flooding wasn't extensive in Manhattan during the storm, but it caused some spectacular damage where it did occur, inundating subway stations and tunnels, crippling critical electrical infrastructure and destroying the mechanical equipment in waterfront skyscrapers.

WSJ: New FEMA flood maps for NYC include WTC site