Measurement of Ice Accretion Using Ultrasonic Pulse-Echo TechniquesAircraft icing remains one of the most severe aviation weather hazards. A system to measure aircraft ice accretion and accretion rate in real time could directly reduce this hazard. Real-time measurement of ice accretion rate can provide the pilot with a quantitative evaluation of icing severity. Therefore, the effectiveness of changes in flight path to minimize ice accretion can be determined. In addition, an automatic measuring system system measuring ice accretion on critical components such as wings, engine inlets, propellers, or rotor blades could be used to automatically activate and optimally control ice protection systems. Although many schemes have been suggested for measuring aircraft ice accretion,1-3 there is still a need for a practical system capable of real-time in situ measurement of ice accretion. The purpose of this study is to evaluate the feasibility and potential performance of an ice detection system using pulsed ultrasonic waves to measure ice thickness over a small transducer mounted flush with the aircraft surface. Since the technique of ultrasonic "pulse-echo" thickness measurement produces a real-time ice thickness signal, the ice accretion rate may be determined by electronically differentiating this thickness measurement with respect to time.
--J. Hansman, Jr., and M. S. Kirby, "Measurement of Ice Accretion Using Ultrasonic Pulse-Echo Techniques," Proceedings, American institute of Aeronautics and Astronautics