What was found
(CAN) AS PILOT ATTEMPTED TO TAXI AWAY FROM DOCK HE REALIZED HE COULDN`T GET OFF THE STOP LOCKS, MEANING HE HAD LITTLE OR NO REVERSE. AIRCRAFT REPAIR SERVICE REMOVED THE PLANE FROM THE WATER & INSPECTED THE PILOTS DEFECT. IT WAS THEN WE HAD REALIZED AFTER TRYING THE POWER LEVER CONTROL THAT THE POWER SHAFT IN THE FCU HAD A SIGNIFICANT AMOUNT OF FREE PLAY. AS WE DISCONNECTED THINGS TO TROUBLESHOOT MORE OF THE PROBLEM, ONE OF THE MECHANICS PULLED UP ON THE SHAFT AFTER WORKING IT THROUGH A COUPLE MORE TIMES IT RELEASED FROM THE FCU. THE POWER SHAFT WAS THEN DISCOVERED TO BE SHEARED OFF, BROKEN INTERNALLY.