What was found
AT FL280 APPROXIMATELY 25 MINUTES INTO FLIGHT LEFT WING BEGAN VENTING FUEL STARTING AT 2900 LBS IN WING (NO FUEL IN CENTER TANK), VENTING CONTINUED THROUGH DESCENT. OPENED LEFT WING FUEL BAY PANELS 552AB, 542DB, 541DB, 551AB, 511CB, & 511AB. INSPECTED SURGE TANK, VENT FLOAT VALVE, SURGE TANK FLAPPER VALVE AND CLIMB VENT LINE. FOUND LT VENT TUBE ASSY AT WS 54.85 1.0 INCH FROM TOP SKIN, REPOSITIONED VENT TUBE IAW CESSNA MM CHAPTER 28-12-00 AND 28-10-04, REFUELED LT WING. VENT AND LEAK CHECK NORMAL.