LOSS OF ELECTRICAL PWR AND EMJ ACFT EVACED WHEN APU EMITS SMOKE AFTER FAILING TO STAY ON LINE AT THE RAMP AFTER ARR AT RIC; VA.

Narrative

APU STARTED NORMAL AFTER LNDG IN RIC. UPON ENTERING THE RAMP IN RIC; APU GENERATOR OFF BUS CAUTION ILLUMINATED ON EICAS. AFTER PARKING AT GATE; ENG WAS SHUT DOWN TO PREVENT ACFT FROM BEING ON BATTERY PWR IF THE APU GENERATOR WOULD NOT RESET. FOLLOWING AOM PROCS; THE ACFT WENT COMPLETELY BLACK AS IT APPEARED THAT THE #1 DC BUS WENT OFF LINE. NUMEROUS WARNINGS AND CAUTIONS ILLUMINATED ON EICAS. APU GENERATOR WAS IMMEDIATELY DESELECTED AND THE #2 ENG WAS SHUT DOWN. SMOKE WAS SEEN BLOWING PAST FO'S SIDE WINDOW. NO SMOKE OR FIRE WARNING FROM EICAS. FLT ATTENDANT ADVISED THAT HE COULD SMELL SMOKE IN CABIN. I EXITED THE COCKPIT AND VISUALLY CONFIRMED THAT HVY BLACK SMOKE WAS EXITING THE APU INTAKE DUCT. APU FUEL SHUTOFF AND APU FIRE EXTINGUISHER WAS PRESSED. FLT ATTENDANT WAS ADVISED TO EXPEDITE DEPLANING REMAINING PAX. ADVISED RAMP TO CALL FOR CFR EQUIP. SMOKE DISSIPATED SHORTLY AFTER THE FIRE EXTINGUISHER WAS ACTIVATED. UNABLE TO DE-POWER THE ACFT USING NORMAL CHKLIST. AFTER CONSULTING WITH MAINT AN ELECTRICAL RESET WAS PERFORMED. ACFT SUCCESSFULLY DE-PWRED. NO INJURY OR HARM TO PAX OR CREW.