A brake control system of the present disclosure calibrates a servo valve and calculates a calibrated transfer function associated with the servo valve for precise braking in open-loop mode. The calibration steps may include determining i) whether an aircraft is on a ground surface, ii) whether the aircraft is not moving relative to the ground surface, and iii) whether braking is applied to a brake system of the aircraft. The brake control unit may calibrate the servo valve in response to the brake control unit determining that i) the aircraft is on the ground surface, ii) the aircraft is not moving relative to the ground surface, and iii) the braking is not applied to the brake system of the aircraft. The calibration process includes sending two or more test currents to the servo valve, and determining braking pressures associated with those test currents to calculate the transfer function.