Flight Testing a Liquid Ice Protection System on a Single-Engine Airplane

A fluid depressant ice protection system has been installed on a Cessna 206 airplane. The system exudes an ethylene glycol solution over the leading edges of the wings, empennage, and lift struts. A slinger ring is used to distribute fluid to the propeller. The windshield is de-iced with a glycol spraybar. The system adds about thirty pounds to the empty weight of the airplane.

Installation of ice protection equipment on a fixed-gear, single-engine airplane presents some unique instrumentation problems since probes must avoid the residual glycol spray from the propeller. Satisfactory anti-icing performance has been demonstrated within the FAR 25, Appendix C continuous maximum and intermittent maximum envelopes during flights in natural icing conditions.