What was found
ON TAKEOFF PILOT HEARD A VERY LOUD "BANG" INSIDE THE CABIN. PILOT LOWERED POWER AND SET THE AIRCRAFT BACK DOWN WHERE IT STARTED FROM. DURING INSPECTION BY MAINTENANCE IT WAS FOUND THAT UNDER THE CORRECT CONDITIONS, ROTATING THE TAIL ROTOR CAUSING ROTATION OF THE INPUT SHAFT INTO THE TRANSMISSION WITH NO ROTATION OUT OF THE MAIN ROTOR TRANSMISSION. THERE WAS A "RATCHETING" FEEL WITH SOME DRAG BUT THERE IS DEFINITELY SLIPPING INSIDE THE TRANSMISSION. ***NOTE THIS AIRCRAFT REMAINS OUT OF SERVICE AT THIS TIME AS REPAIRS ARE STILL IN WORK***