20110228003229I

Flight 668, arrived in Atlanta, Georgia (atl), gate A-13 and utilized external power after engine shutdown. After passengers began deplaning normally through the main cabin door, the captain (who was in the flight deck entry door) observed smoke in the external power receptacle area. The smoke eventually entered the aircraft through the main passenger entry door. The captain then verbally directed the lead flight attendant to evacuate out the main cabin door, however, passengers at the exit rows began to exit the aircraft through the over wing exits. Three passengers from the over wing exits egressed to the ramp and other passengers were on the left and right wings. The aft flight attendant decided to use the tail cone emergency exit, but it was not operable. In her statement, she indicated that she attempted to use the forward and aft release handles (located in the tail cone area) but to no avail. The rear stairs were lowered (presumably by ground personnel) and one passenger was able to walk down to the ramp prior to the flight attendant blocking the exit as unusable. At some point, the rear tail cone jettisoned with the rear escape slide inflating. It is still unclear why the tail cone and slide deployed late, therefore, an investigation continues to determine the reason for the malfunction. The captain halted the evacuation when he determined the fire was out. The passengers on the wings were brought back into the aircraft through the emergency exits, and deplaned normally. Based on an on scene investigation by an FAA inspector from the dal atl cmu, it appears that there was intense heat from arcing in the external power receptacle, but no fire. The aircraft received damage to the aluminum structure around the external power receptacle as well as the receptacle itself. A pertinent maintenance discrepancy was noted on February 4, 2011 when maintenance personnel replaced the external power monitor. This incident was reported to the NTSB pursuant to part 830. There were no injuries reported.