As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT WING NACA VENT PORTING FUEL ONTO GROUND AND DURING CLIMB WHEN OVER 11000 LB OF FUEL PUT INTO WING. EVENTUALLY FOUND MISSING O-RING P/N MS29513-337 IN OUTBOARD VENT COUPLING P/N 12J36-48A. THIS WAS REPLACED BY MFG TECHNICIANS AT OPERATOR'S FACILITY. FUNCTIONALLY CHECKED WITH WING FULLY LOADED WITH FUEL. IT WAS OBVIOUS THAT THIS WAS CAUSED BY THE AIRFRAME MANUFACTURER AND WAS NOT PROPERLY TESTED.