As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ANNUAL INSPECTION, PITOT MAST WAS CHECKED FOR PROPER OPERATION OF THE HEATER. WHILE THE MAST WAS WARM TO THE TOUCH, IT WAS NOT REALLY GETTING HOT. FURTHER INVESTIGATION SHOWED THAT ONE OF THE HEATING ELEMENTS WAS BURNED OUT. P/N INVOLVED 464-356 AND 464-357.