What was found
AT APPROXIMATELY 300 FEET ALTITUDE, PILOT HEARD A LOUD BANG AND EXPERIENCED AN IMMEDIATE LOSS OF POWER. ATTEMPTED EMERGENCY LANDING RESULTED IN SUBSTANTIAL DAMAGE TO AIRCRAFT BOOM AND MAIN ROTOR BLADES. INVESTIGATION AND ANALYSIS DETERMINED THE MAIN DRIVE BELT SUFFERED A CRIMP TYPE FAILURE IN FLIGHT. THIS DRIVE BELT IN MANUFACTURER CATALOG INTRODUCTION SPECIFICALLY STATES IN THEIR AIRCRAFT POLICY THAT THEIR BELTS ARE NOT INTENDED FOR AIRCRAFT USE. SUSPECT BELT FAILURE WAS A RESULT OF EXPOSURE TO UNDER TENSION.