What was found
DURING A 500 HOUR INSPECTION IT IS NECESSARY TO DISSASSEBLE THE MAIN ROTOR FREQUENCY ADAPTER TO INSPECT FOR CORROSION. THE BEARING THAT IS IN THE ADAPTER IS SUPPOSED TO BE EASILY REMOVABLE. VARIOUS EFFORTS WERE MADE TO REMOVE THE BEARING. THE BEARING WAS REMOVED BY EXCESSIVE FORCE TO TRY TO FIND OUT WHY IT WAS FROZEN IN PLACE. AIRCRAFT'S ADAPTERS WERE ASSEMBLED WITH MINIMAL AMOUNTS OF A COMPOUND CALLED "MASTINOX" I.A.W. THE M/M. WHEN THE BEARING WAS REMOVED, CORROSION WAS FOUND IN THE BEARING BORE AND ON THE RETAINING RING. ALL THREE FREQUENCY ADAPTERS WERE IN THE SAME CONDITION AND ALL THREE REPLACED.