Abstract: A method and apparatus for measuring the thickness of ice on an aircraft member is disclosed. In the preferred embodiment, the apparatus is mounted beneath an aircraft member surface. The apparatus includes transducers for transmitting ultrasonic signals through the aircraft member and ice at predetermined applied voltages and frequencies. The apparatus measures the current and phase angle relative to voltage associated with each transducer and frequency. The apparatus calculates the impedance of the transducer transmitting through aircraft member and any ice accumulation from the applied voltage and measured current and phase angle relative to voltage at each of the predetermined frequencies. The apparatus then computes the ice thickness by determining the frequencies where the impedance is a peak. The invention also broadly comprises an apparatus and a method for the detection of ice on an aircraft member.

Abstract: A method and apparatus for measuring the thickness of ice on an aircraft member is disclosed. In the preferred embodiment, the apparatus is mounted beneath an aircraft member surface. The apparatus includes transducers for transmitting ultrasonic signals through the aircraft member and ice at predetermined applied voltages and frequencies. The apparatus measures the current and phase angle relative to voltage associated with each transducer and frequency. The apparatus calculates the impedance of the transducer transmitting through aircraft member and any ice accumulation from the applied voltage and measured current and phase angle relative to voltage at each of the predetermined frequencies. The apparatus then computes the ice thickness by determining the frequencies where the impedance is a peak. The invention also broadly comprises an apparatus and a method for the detection of ice on an aircraft member.