A CL65 IN DSCNT AT 10000 FT. ON AUX POWER UNIT START; JET 'A' FUEL FUMES THROUGH THE AIR CONDITIONING SYSTEM WERE DETECTED IN THE COCKPIT AND CABIN ALMOST IMMEDIATELY. THE APU WAS SHUT DOWN IMMEDIATELY AND THE FUMES DISSIPATED.

Narrative

UPON DSCNT INTO ZZZ; APU PRODUCED JET A FUMES FROM AIR CONDITIONING SYSTEM IMMEDIATELY AFTER START-UP. WE THEN IMMEDIATELY SHUT DOWN THE APU AND FUMES DISSIPATED. LANDED IN ZZZ MINUTES LATER WITH NO FURTHER INCIDENT. MAINT CALLED; APU INSPECTED. APU DEFERRED.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE WAS IN DSCNT AT 10000 FT; 20 MILES FROM THE ARPT AND THE AUX POWER UNIT WAS STARTED AND SELECTED FOR PNEUMATICS FOR THE AIR CONDITIONING PACKS. THE FUMES FROM JET A FUEL WERE IN THE CABIN AND COCKPIT ALMOST IMMEDIATELY AND THE AUX POWER UNIT WAS SHUT DOWN. THE RPTR INDICATED THAT ON LNDG; MAINT CTL WAS CALLED AND ADVISED OF THE FUEL FUMES IN THE CABIN AND COCKPIT AND THE DECISION WAS MADE TO DEFER THE AUX POWER UNIT AS INOP PER THE MEL. THE AUX POWER UNIT WAS A GARRETT GTCP 36-150. THE RPTR STATED THERE WAS ONE OTHER INCIDENT IN THE FLEET OF FUEL FUMES ENTERING THE CABIN AND COCKPIT BUT HAS NO INFO ON THE FIX ON THE PREVIOUS INCIDENT AND THIS INCIDENT.