What was found
ON LANDING AT ACK, NOSE LANDING GEAR FAILED. PILOT HAD 3 GREEN DOWN AND LOCKED INDICATIONS PRIOR TO AND AFTER LANDING. AFTER SECURING GEAR DOWN AND LOCKED, REMOVING AND REPLACING BOTH PROPELLERS, AN ENGINE RUN UP, AND INSPECTION, AIRCRAFT FERRY FLOWN TO MAINTENANCE BASE FOR FURTHER INVESTIGATION. PART WAS INSPECTED AND OVERHAULED. UPON INITIAL INSPECTION NO DAMAGE WAS NOTED. UPON TEARDOWN EVIDENCE OF WATER WAS FOUND IN COVER. SUSPECT FREEZE UP OF TOWER AND SWITCH MECHANISM. UNIT HAS BEEN RETURNED TO SERVICE.