A CL65 ON APCH; AT 5000 FT APU STARTED AND PACKS SWITCHED TO APU PNEUMATIC AIR WHEN CABIN FILLED WITH STRONG ODOR OF RAW FUEL.

Narrative

DESCENDING TOWARDS DEST ARPT; WE ATTEMPTED TO START THE APU UNSUCCESSFULLY. 2ND ATTEMPT WAS SUCCESSFUL. UPON TRANSFERING PACKS TO APU BLEED AIR SOURCE A STRONG ODOR OF RAW FUEL FILLED THE CABIN AND COCKPIT. I AND FO DONNED OUR OXYGEN MASKS AND EXECUTED QRH PROCS. DECLARED AN EMER AND LANDED. WE TURNED OFF THE APU AND PUT THE PACKS BACK ON ENG BLEED AIR WHICH CLRED THE SMELL. AFTER LNDG CFR AND MYSELF DETERMINED WE COULD NOT SEE ANY FUEL LEAKING. MAINT LATER FOUND FUEL POOLED AT THE BOTTOM OF THE APU FIRE CONTAINMENT BOX. INCIDENTLY THE SAME PROB SEEMS TO HAVE HAPPENED ON 01/01/FRI. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE STRONG ODOR OF FUEL REQUIRED THE USE OF OXYGEN MASKS IN THE COCKPIT. THE RPTR SAID IT WAS LIKE SOMEONE DUMPED A BUCKET OF KEROSENE IN THE CABIN AISLE. THE RPTR STATED THE APU HAD BEEN RPTED IN THE LOGBOOK 4 OR 5 TIMES FOR HARD STARTING AND SMELL OR FUMES IN THE CABIN. THE RPTR SAID A CONTRACT MECH CHKED THE PWR UNIT AND FOUND FUEL POOLED IN THE BOTTOM OF THE APU SHROUD. THE RPTR SAID THE FUEL WAS CLEANED UP AND THE AUXILIARY PWR WAS DEFERRED PER THE MEL. THE RPTR STATED HE FOLLOWED THE AIRPLANE MAINT HISTORY AND IT WAS AGAIN RPTED CAUSING FUMES OR AN ODOR IN THE CABIN.