As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING GEAR SWING, FOUND MAIN GEAR ACTUATOR JAM NUT LOOSE. THIS IS THE 2ND CARDINAL RG FOUND THIS WAY. FIRST CARDINAL, THE ROD END HAD ROTATED OUT OF PISTON ENOUGH TO CAUSE GEAR NOT TO LOCK DOWN. THERE IS NO SAFETY ON JAM NUT TO PREVENT BACKING OFF OF ROD. SUBMITTER RECOMMENDS CHECKING JAM NUT WHENEVER ACTUATOR IS ACCESSIBLE.