What was found
THE AIRCRAFT WAS LOCATED ON A HELIPAD, ON START UP THE PILOT NOTICED A ABNORMAL VIBRATION AT APPROX 45 PERCENT N1 / 25 PERCENT ROTOR, AND ABORTED THE START. UPON FURTHER INSPECTION A DENT APPROX 5 INCHES LONG, AND A TEAR APPROX 4 INCHES LONG, ON THE LEADING EDGE OF THE VERTICAL STABILIZER STARTING APPROX 5 INCHES BELOW THE GEARBOX MOUNT AND CONTINUING DOWNWARD TOWARD THE LEFT HAND SIDE WERE DISCOVERED. THE DAMAGED WAS DETERMINED TO BE UNAIRWORTHY. SUSPECTED CAUSE OF DAMAGE IS ICE BEING SLUG FROM THE MAIN ROTOR OR MAIN ROTOR HUB DURING THE START PROCEDURE. ICING CONDITIONS WERE PRESENT AT THE TIME. TT 7012.4 TOTAL LANDINGS: 22,595