Ice detection system for control surfaces of aircraft and related method

Ice detection system (2) for control surfaces (S) of aircraft (A) whereon a layer (L) of water and/or ice may be present. The system comprises: a support structure (20); a fist sensor (3) of the capacitive type, adapted to detect the electrical properties of the layer (L) of water and/or ice; and a second sensor (4) of the ultrasonic type, adapted to detect the mechanical properties of the layer (L) of water and/or ice. The second sensor (4) comprises: an ultrasonic transceiver (41) adapted to generate ultrasonic waves to be transmitted, and to receive the ultrasonic waves reflected by the layer (L) of water and/or ice on the surface (S); a delay line (42), arranged between the ultrasonic transceiver (41) and the surface (S), through which the transmitted and reflected ultrasonic waves are propagated. The delay line (42), which extends along an axis (X), comprises a first line (42A) and a second line (42B) parallel or coaxial to each other. The length of the first line (42A) along said axis (X) is greater than that of the second line (42B), resulting in at least two different reflected ultrasonic waves. The sensors (3, 4) are arranged in the support structure (20), thus defining a compact single measurement system.