As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKE-OFF FROM YYR THE FLIGHT CREW NOTED THAT THE LEFT MAIN FUEL CAP CAME OFF AND EXITED THE AIRCRAFT. THE AIRCRAFT RETURNED TO BASE. MAINTENANCE INSPECTED THE FUEL FILLER OPENING AND WING CAP FITTING. NO DEFECTS WERE NOTED. THE MISSING FUEL CAP WAS NEVER FOUND. ALL FUEL CAPS ON THIS AIRCRAFT TYPE IN THE FLEET WERE THEN INSPECTED WITH NO DEFECTS NOTED.