Based on the dual redundancy flaps slat electronic control unit (FSECU) architecture, a sum monitoring algorithm was first proposed to confirm the validity of the flaps slat control lever (FSCL), and then a cross matching voting algorithm was proposed to vote the final valid detent signal. However, this algorithm was greatly affected by the accuracy of the handle and the signal transmission time, and it was easy to cause the flaps and slat system to move at half speed. In order to improve the robustness of the algorithm, an improved voting algorithm of FSCL was further proposed. When the signals of one channel and the other three channels are inconsistent, the detent of most channels shall prevail. When the signals of the two channels are inconsistent, the detent of the changed channel shall prevail. When the above two cases occur more than three times, the fault is latched, and the bad detent signal will trigger a half-speed alarm to avoid hidden faults. The above scenarios are verified by modeling and simulation in MATLAB&Simulink environment, and the results are in line with expectations, which can provide reference for the design of FSECU.