Abstract: An airborne Icing Hazard Detector for aircraft uses dual frequency radar beams which are transmitted into a cloud ahead of the aircraft. The reflected signals at each of the two frequencies are compared and processed to determine the presence, amount and location of regions of liquid water in the cloud. The presence of liquid water is determined as a result of liquid water attenuating the power of one of the signals a greater amount than the other signal, due to different attenuation characteristics of the two signals at the two frequencies. A temperature sensor provides ambient temperature information to determine if the detected liquid water is super-cooled. Upon detection of a predetermined amount of liquid water and the determination that it is super-cooled, an advance warning indication is provided to allow the pilot to avoid flying through the volumetric region of supercooled liquid water and risking ice formation on the aircraft.