As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AD HAS YOU PERFORM PRESSURE LEAKAGE CHECK ON THESE HEATER FUEL PRESSURE REGULATORS. WHEN NEW AND BEFORE INSTALLATION INTO AIRCRAFT. WE FIND THAT MANY OF THESE UNITS FAIL AFTER A SHORT TIME OF USE. THEY START LEAKING AROUND HOUSING DIAPHRAGM AND NOTICED FUEL STAIN FROM DRAIN ON THE NOSE SECTION OF THE AIRCRAFT.