Hydrogen and hydrocarbon detection in aeronautical applications is important for reasons of safety and emissions control. The use of silicon carbide as a semiconductor in a metal-semiconductor or metal-insulator-semiconductor structure opens opportunities to measure hydrogen and hydrocarhona in high temperature environments beyond the capabilities of silicon-based devices. The purpose of this paper is to explore the response and stability of Pd-Sic Schottky diodes as gas sensors in the temperature range from 100 °C to 400 °C. The effect of heat treating on the diode properties as measured at 100 °Cis explored. Subsequent operation at 400 °C demonstrates the diode's sensitivity to hydrogen and hydrocarbons. It is concluded that the Pd-Sic Schottky diode has potential as a hydrogen and hydrocarbon sensor over a wide range of temperatures hut further studies are necessary to determine the diode's long term stability.