A fault detection system to detect faults relating to an aircraft braking system comprising at least one brake, the fault detection system comprising a controller configured to: receive braking demand information relating to a requested braking intensity for a braking event; receive torque information relating to an amount of torque reacted by the at least one brake during the braking event; receive wear information relating to a wear state of the at least one brake during the braking event; receive wheel speed information relating to a wheel speed of a wheel associated with the at least one brake during the braking event; receive brake temperature information relating to a maximum temperature of the at least one brake as a result of the braking event; calculate an expected maximum temperature of the brake as a result of the braking event, based on the received torque information, the received wear information and the received wheel speed information; determine whether a significant temperature discrepancy exists between the calculated expected maximum temperature and the received brake temperature information; determine whether a significant torque-related discrepancy exists based on the received braking demand information and the received torque information; if a significant torque-related discrepancy exists and no significant temperature discrepancy exists, generate a first alert relating to a first fault type; if a significant temperature discrepancy exists and no significant torque-related discrepancy exists, generate a second alert relating to a second fault type; and if a significant temperature discrepancy exists and a significant torque-related discrepancy exists, generate a third alert relating to a third fault type. receive braking demand information relating to a requested braking intensity for a braking event; receive torque information relating to an amount of torque reacted by the at least one brake during the braking event; receive wear information relating to a wear state of the at least one brake during the braking event; receive wheel speed information relating to a wheel speed of a wheel associated with the at least one brake during the braking event; receive brake temperature information relating to a maximum temperature of the at least one brake as a result of the braking event; calculate an expected maximum temperature of the brake as a result of the braking event, based on the received torque information, the received wear information and the received wheel speed information; determine whether a significant temperature discrepancy exists between the calculated expected maximum temperature and the received brake temperature information; determine whether a significant torque-related discrepancy exists based on the received braking demand information and the received torque information; if a significant torque-related discrepancy exists and no significant temperature discrepancy exists, generate a first alert relating to a first fault type; if a significant temperature discrepancy exists and no significant torque-related discrepancy exists, generate a second alert relating to a second fault type; and if a significant temperature discrepancy exists and a significant torque-related discrepancy exists, generate a third alert relating to a third fault type.