What happened
During the approach phase of the flight, the crew lowered the landing gear but observed that none of the gear position lights were illuminated. Prior to touchdown, the captain noted that both the interphone and the public address system were inoperative.
The aircraft completed a visual approach and achieved a normal touchdown. During the landing rollout, the crew discovered that the thrust reversers failed to deploy. After the aircraft exited the runway and transitioned to the taxiway, flight attendants reported the smell of smoke. In response, the captain stopped the aircraft on the taxiway and ordered an emergency evacuation. During the use of the emergency slide, one passenger sustained a minor sprain.
The investigation
An inspection of the aircraft revealed that a multiple system loss had occurred because the 28-volt DC battery bus went offline. Investigators were able to duplicate the condition during troubleshooting processes. The investigation identified the failed component as a battery transfer relay (R2). While smoke was reported by the crew, the specific source of the onboard smoke was not identified.