As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT WING FUEL SAMPLE DRAIN VALVE DRIPPING AND THEN REMAINING OPEN. UPON DISMANTLE, THE O-RING WAS FOUND BROKEN IN 3 PLACES AND SEPARATED INTO 2 PIECES. THE BROKEN O-RING PIECES LODGED IN THE FORWARD FLOW HOLES AND KEPT THE VALVE STEM OPEN. UPON MEASUREMENT OF THE VALVE STEM DIAMETER AT THE O-RING POSITION, THE DIAMETER WAS .028 INCH LARGER THAN A VALVE STEM REMOVED EARLIER.