As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FUEL VENTED FROM LT IB FUEL CAP ON TAKEOFF. AIRCRAFT RETURNED TO BASE AND UPON INSPECTION FOUND THE CAP WAS LOOSE WHEN LATCHED. THE COTTER PIN WAS MISSING AND IT AND THE ADJUSTMENT NUT HAD LOOSENED. ADJUSTED CAP AND REPLACED COTTER PIN.