BE58 PLT RETURNS TO DEP ARPT WHEN FUEL CAP COMES OFF OF LEFT WING TANK.

Narrative

I COMPLETED REFUELING THE BARON AND CONDUCTED MY PREFLT. LATER; I BEGAN MY TKOF ROLL ON RWY 17. I WAS CLRED FOR A L TURN OUT AS ANOTHER ACFT WAS INBOUND TO RWY 35. AS I LIFTED OFF AND WAS PASSING THROUGH 100 FT; I NOTICED THE L FUEL CAP HAD COME OFF; TETHERED BY ITS RETAINING CHAIN AND LAYING ON THE WING WITH FUEL STREAMING FROM THE L TANK. I NOTIFIED THE TWR THAT I NEEDED TO RETURN AND WAS CLRED TO ENTER A L BASE LEG TO RWY 22. I CLBED TO APPROX 700 FT WHILE NOTING THE SLUGGISH RESPONSE OF THE CTLS. WITH THE FUEL STREAMING AS MUCH AS IT WAS AND THE IMAGE OF FIRE PASSING THROUGH MY MIND; I MADE THE DECISION NOT TO USE FLAPS. I BEGAN A STEEPER THAN NORMAL DSNDING L TURN TO RWY 22 AND HAD TO USE 30-35 DEGS OF BANK WITH AIRSPD BTWN 90-100 KTS. AS I WAS APCHING SHORT FINAL AND PASSING THROUGH 300 FT; I TRIED TO ROLL WINGS LEVEL ONLY TO DISCOVER THE L WING DID NOT WANT TO LEVEL OUT. I COULD ONLY ASSUME THAT IT WAS IN A STALLED STATE; WITH LITTLE OR NOT LIFT BEING PRODUCED. I BEGAN ADDING PWR BUT THE DSCNT CONTINUED AT 300-400 FPM. AS I ENTERED GND EFFECT THE L WING STARTED TO RISE BUT WAS STILL L WING DOWN AND NOT LINED UP WITH CTRLINE (THE NOSE ABOUT 20 DEGS TO THE L OF CTRLINE). I WAS ABLE TO DECREASE THE DSCNT RATE SOME BUT NOT ENOUGH TO PREVENT THE L WINGTIP FROM MAKING CONTACT WITH THE GND AT THE SAME TIME AS THE L MAIN MOUNT. HEADING FOR THE GRASS AND THE THOUGHT OF GND-LOOPING THE ACFT OR SIDE-LOADING THE GEAR; I IMMEDIATELY ADDED FULL PWR; REGAINED CTL OF THE ACFT; TAKING FLT AGAIN. ON THE GAR; THE TWR ASKED IF I WANTED TO TEARDROP BACK TO RWY 4 AND I REPLIED YES. I CLBED UP TO 1000 FT; EXECUTED A L TURN TEARDROP AND LANDED WITH NO FURTHER INCIDENT. LOOKING BACK; I SHOULD HAVE TREATED THIS SITUATION AS A NORMAL LNDG. WIDENING OUT THE L BASE TO FINAL MORE WOULD PROBABLY HAVE AVERTED THIS ENTIRE INCIDENT. ALSO; THE USE OF FLAPS WOULD HAVE DECREASED MY STALL SPD TO WHERE THE L WING WOULD NOT HAVE LOST THE AMOUNT OF LIFT THAT IT DID DURING THE DSNDING L TURN. ALTHOUGH; THE THOUGHT OF A FIRE STILL RAISES MY ANXIETY LEVEL. THE BEST FIX IS NOT TO HAVE THE INITIAL PROB HAPPEN IN THE FIRST PLACE; IF POSSIBLE.