As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE LEFT FORWARD ENTRY DOOR WAS EXTREMELY HARD TO ARM. THE ACFT WAS GROUNDED AND THE DOOR LATCH AND LOCK MECHANISM WAS INSPECTED INTERNALLY AND EXTERNALLY IAW AMM 52-12-25. THE ASSEMBLY WAS CLEANED AND A SATISFACTORY OPERATIONAL CHECK OF THE DOOR LATCH AND LOCK WAS PERFORMED. THE CAUSE OF THE STIFF ARMING HANDLE IS UNKNOWN.