As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ATC REPORTED THAT THE LT TANK WAS VENTING FUEL DURING TAKE-OFF. NO EMERGENCY WAS DECLARED - PRIORTY HANDLING AND RETURN REQUESTED AND ASSIGNED FOR RETURN. INSP PERFORMED ON THE GROUND W/NO DEFECTS NOTED. SWAPPED FUEL CAPS FROM LT TO RT, PERFORMED A RUN-UP, LEAK CHECK GOOD. IN CONCLUSION, THE FUEL CAP WAS NOT PROPERLY SECURED.