At about 0725 Central time, the airplane, operating as United Airlines Flight 497, exited the left side of a runway after returning due to automated warnings of smoke in an equipment bay. The airplanes nose wheel exited the side of the runway upon completing the landing roll and an emergency evacuation was conducted. The airplane, with 109 passengers and crew aboard, had departed about 20 minutes earlier. The passengers and crew exited the airplane via slides. There were no reported injuries. Initial information is that the airplane had minor damage. The crew reported the airplanes electronic centralized aircraft monitor system provided an autothrottle-related message and an avionics smoke warning message, accompanied by instructions to land while climbing through 4000 feet msl. The flight crew did not smell smoke or fumes during the flight. A loss of primary instrumentation also was reported during the event. The crew initiated emergency procedures and turned back to the airport. The crew also described a loss of anti-skid braking and nosewheel steering upon landing and left the runway approximately 2000 feet from its departure end. Additionally, the forward right-hand slide reportedly failed to inflate during the emergency evacuation.
