Nowadays position pickup units are commonly used in order to measure the rotation position of a shaft for operating a landing flap or landing slat or a brake flap in an aircraft. In the case of failure of such a position pickup unit (PPU) the corresponding drive motor of the shaft has to be switched off because position data is no longer present. According to one embodiment of the present invention a device for determining the rotation angle of a shaft in an aircraft is stated, with said device comprising a shaft and a motor, wherein rotation of the shaft is measured by way of the motor. This measuring data can be evaluated together with the data of the PPU. In this way improved system availability is ensured.