ACFT EQUIP PROB APU FUEL LEAK.

Narrative

THE ACFT HAD MAINT PERFORMED THE PREVIOUS DAY TWICE FOR THE SAME FUEL LEAK. WHEN MY CREW PICKED UP THE ACFT THE FOLLOWING DAY; I SAW THAT FUEL WAS STILL LEAKING AT THE SAME AREA. I WROTE THE LEAK UP IN THE LOGBOOK. THIS WAS IN HVN. OUR COMPANY HAS NO MAINT IN HVN; SO A MECH FROM THE FBO WAS BROUGHT TO THE ACFT. HE CLEANED THE LEAKED FUEL FROM THE AFFECTED AREA -- THE ENG NACELLE AND LNDG GEAR WELL (L SIDE OF ACFT). NO FURTHER LEAKING WAS NOTED; SO THE ACFT L ENG WAS RUN UP TO POSSIBLY INDUCE THE LEAK. AFTER 2 RUNUPS; NO LEAK COULD BE FOUND. THE MECH THEN OPENED UP ALL ENG ACCESS PANELS FOR FURTHER EXAMINATION. AGAIN; NO LEAK WAS FOUND. ACFT WAS AGAIN RUN UP. STILL NO LEAK FOUND. COMPANY MAINT DIRECTED; VIA TELEPHONE; THAT THE ON-SITE MECH SIGN OFF THE ACFT LOGBOOK AS OK FOR CONTINUED REVENUE SVC. I EXPRESSED SOME RESERVATIONS; AS WE HAD AN UNKNOWN; YET CONTINUOUS; FUEL LEAK. MAINT ASSURED ME THAT THE LEAK WAS IN A 'BLOW-DOWN' CHK VALVE AND IF IT WERE TO LEAK AGAIN; IT COULD ONLY BE AT ENG SHUTDOWN; AND ONLY A MINIMAL AMOUNT OF FUEL COULD LEAK. THEY ALSO SUGGESTED THAT THE CHK VALVE HAD PROBABLY RE- SEATED AND MOST LIKELY WOULDN'T LEAK AGAIN ANYWAY. WE WERE SCHEDULED TO FLY TO BWI WHERE THE CHK-VALVE WOULD BE REPLACED AS A PRECAUTION. I WAS SOMEWHAT SKEPTICAL; AS THE 2 PREVIOUS 'FIXES' FAILED TO STOP THE FUEL LEAK. AFTER BEING REPEATEDLY ASSURED THAT AN INFLT FUEL LEAK WAS IMPOSSIBLE; I DEPARTED FOR BWI WITH PAX. UPON ARR AND SHUTDOWN; FUEL WAS LEAKING AGAIN. AS IT TURNED OUT; AN APU WAS INSTALLED IN THE ACFT A COUPLE DAYS PRIOR. THE APU IS FUELED FROM THE L TANK. THE FUEL LINE TO THE APU WAS IMPROPERLY INSTALLED CAUSING THE LEAK AT THE TANK CONNECTION TO THE APU FUEL LINE. FUEL HAD BEEN LEAKING OUT OF THE TANK AND OVER THE ENG JET-PIPE! OUR RTE OF FLT TOOK US OVER WATER. AN INFLT FIRE WAS ENTIRELY POSSIBLE AND WOULD HAVE BEEN CATASTROPHIC. I AM CONCERNED THAT ACR MAINT COULD NOT GET A 'HANDLE' ON THIS PROB; TAKING 4 FIXES TO GET IT RIGHT. I AM ALSO CONCERNED THAT THEY LED ME TO BELIEVE THAT THERE WAS NO REAL PROB.