What happened
Shortly after departure, the flight crew of an Airbus A320 (registration not provided) received a Brake and Steering Control Unit (BSCU) channel 2 fault message. After reaching 10,000 feet, the crew attempted to reset the BSCU according to the cockpit operational manual; however, the channel 2 fault returned. This prevented the crew from turning off the auto brakes or changing the brake setting from "Maximum." The crew confirmed they had "yellow" brake pressure, utilizing alternate brakes and the parking brake, and prepared to land using this configuration.
Because disabling the antiskid and nosewheel steering would also disable maximum braking, the crew discussed landing with these systems in the "Off" position if necessary. During the first approach, while extending the landing gear, the crew received a landing gear shock absorber fault indication, which caused the auto throttles and autopilot to disconnect. The captain reported that the landing gear remained down and flaps were raised. The first officer followed manual procedures and notified maintenance control of the shock absorber fault.
After receiving vectors for final approach, the crew set the flaps to full and completed the landing checklist. The plan was to maintain low brake pressure during landing and use manual braking to bring the aircraft to a stop before re-engaging nosewheel steering to taxi to the gate. The crew did not notify air traffic control of their specific situation. Upon touchdown, the crew felt a vibration, and air traffic control reported seeing flames near the nose gear. The aircraft came to rest on the runway with the nose gear strut turned 90 degrees from the direction of landing. The lower half of both the nose gear tire and wheel assembly was ground away due to contact with the runway. There were no injuries and the nose gear was the only part of the aircraft that sustained damage.
The investigation
Post-incident examination and testing of the nose landing gear systems identified an unidentified, intermittent failure of an integrated circuit on the BSCU monitor board. This failure most likely caused the BSCU System 1 analog and discrete outputs to freeze. While BSCU System 2 could detect the System 1 failure, it was unable to take control of the system.