High temperature piezoelectric crystal (HTP) sensors are desired for future propulsion component structure health monitoring, operating parameters optimization, turbine engine control and health monitoring, as well as improving performance and maintainability of power production facilities and other rotary combustion engines. Recently discovered high temperature piezoelectrics showed stable piezoelectric properties and high resistivity at temperatures close to its melting point (~ 1500 C) , which is very promising for high temperature sensor applications. The preliminary results showed excellent temperature sening performance at temperature up to 1000 C. Piezoelectric structural sensors on the basis of piezoelectric effect (non-resonant) and impedance measurement (resonant) have been widely demonstrated for pressure, stress, strain, temperature, acceleration, etc. measurements because of their high sensitivity, quick response, low profile, high reliability and low cost. The goal of this program is to develop highly sensitive HTPC based piezoelectric structural sensors for temperature, strain and acceleration measurements at temperatures up to 2000 oF.