Detection of Ice and De-Icing/Anti-Icing Fluids on Aircraft Surfaces Using Time Domain Reflectometry

Abstract

Time domain reflectometry is a practical and effective way to detect ice, frost, moisture, anti-icing/de-icing aircraft fluids (ADAFs), and mixtures of each on aircraft surfaces. Using this method, a passive sensor is placed at the end of a transmission line. A fast rise-time pulse excites the transmission line and is reflected from the sensor upon its arrival at the end of the line. The detailed shape of the reflected waveform depends on the dielectric properties of the fluid in contact with the sensing electrodes. Multiple sensors were constructed and tested to determine the suitability and reliability of varying designs. A software protocol was also developed to detect phase transitions and alert pilots with a binary response that indicates a safe or hazardous condition. In effect, this system would help reduce the volume of ADAFs applied and increase the safety of air travel.