As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN DOOR: MAIN CABIN DOOR IS VERY HARD TO OPEN. // SIGNOFF// OPS CHECKED MAIN CABIN DOOR AND DOOR PERFORMS WITHOUT MECHANICAL DEFECTS BUT OPERATION IS STICKY. CLEANED AND LUBRICATED DOOR PINS WITH MOLYKOTE G-N AND PERFORMED OPERATIONAL CHECKS WITH NO FURTHER DEFECTS NOTED REF. CESSNA MODEL 560XL AMM 12-20·52.