CL65 RETURNED TO DEP STATION WITH FUEL TRAILING FROM A TANK WITH A TANK CAP LEFT OFF BY THE FUELER.

Narrative

WE ARRIVED IN DFW. FO PERFORMED POSTFLT INSPECTION; FOUND NO DISCREPANCIES. WE LEFT ACFT TO GET FOOD. ON RETURN TO ACFT; FO PERFORMED PREFLT INSPECTION. FOUND NO DISCREPANCIES. THE FUELER DID NOT ARRIVE TO FUEL US UNTIL NEAR DEP TIME. THERE WAS SOME CONFUSION; AS THE FUELER TOLD THE FO THAT HE HAD PUT FUEL INTO THE CTR TANK; AND HAD TO 'DRAIN IT.' THIS MAKES NO SENSE; AS WE CAN HAVE UP TO 500 LBS OF FUEL IN THE CTR TANK WITHOUT FULL MAIN TANKS. ALSO; THE ONLY WAY TO 'DRAIN' FUEL IS TO PRESSURE DE-FUEL THROUGH THE PRESSURE FUELING SYS; WHICH REMOVES FUEL FROM THE ENTIRE SYS. AFTER TELLING THE FUELER NOT TO WORRY ABOUT FUEL IN THE CTR TANK; THE FO CHKED TO SEE THAT THE PRESSURE REFUELING SYS WAS SECURED FOR FLT; AND RPTED TO ME THAT IT WAS. OUR PREFLT PROCS ONLY REQUIRE THE CHKING OF THE FUELING SYS ACTUALLY USED. AFTER TKOF; TWR RPTED THAT WE SEEMED TO BE TRAILING SOMETHING. THE ACFT BEHIND US RPTED THAT HE HAD A STRONG RAW FUEL SMELL AND AN OILY SUBSTANCE ON HIS WINDSCREEN. I IMMEDIATELY LEVELED OFF AT 3000 FT AND TURNED A R DOWNWIND FOR THE NEAREST RWY. I DECLARED AN EMER; AS THE FO ADVISED THE FLT ATTENDANT OF OUR RETURN. I ASKED THE TWR FOR THE LOC FREQ. HE DIDN'T KNOW; BUT A LOCALLY BASED CREW DID; AND GAVE IT TO ME. WE LANDED SMOOTHLY AND UNEVENTFULLY. I ELECTED NOT TO USE REVERSE THRUST; FOR FEAR OF BLOWING TRAILING FUEL FORWARD WHERE IT COULD POSSIBLY IGNITE. I CLRED THE RWY; SET THE BRAKE; AND HAD THE FO SHUT DOWN ALL ENGS. CFR ADVISED THAT THERE WAS NO FUEL LEAKING; SO WE KEPT THE PAX SEATED; AS I WENT OUT TO SPEAK WITH THE CFR CREW AND INSPECT THE ACFT TO ASCERTAIN IF ANY STRUCTURAL DAMAGE WOULD PREVENT US FROM TAXIING TO THE GATE; AND IF A FIRE HAZARD REQUIRED THE EVAC OF THE ACFT. IT WAS ON INSPECTION OF THE R WING THAT I FOUND THE FUEL CAP OFF; TRAILING BY ITS LANYARD. THE CAP WAS SECURED; THE ACFT STARTED; AND WE RETURNED TO THE GATE. AN INSPECTION BY MAINT FOUND NO DAMAGE TO THE WING BY THE CAP; AND THE FLT DEPARTED UNEVENTFULLY 1 1/2 HRS LATER. THE NEXT DAY; AS WE PASSED THROUGH DFW AGAIN; THE SAME FUELER FAILED TO SECURE THE PRESSURE FUELING PANEL DOOR COMPLETELY. IT WAS CAUGHT ON WALKAROUND; AND SECURED BY ME.