The article is devoted to solving the problem of determining the electron work function of aircraft metal parts of aviation technology by the Kelvin probe method. The features of the application of the Kelvin probe method for contact potential difference measurement for aircraft metal parts are considered. Requirements for the Kelvin probe developed for measuring the contact potential difference of metal parts are formulated. A comparative analysis of materials for the manufacture of the measuring electrode of the sensor is carried out. A technique is proposed to ensure the stability of the measurement results of the contact potential difference, and the factors influencing it are assessed. Practical recommendations are given for the Kelvin probe development of the contact potential difference measuring on the aircraft metal parts surface.