A CL65 CAPT NOTICED SMOKE COMING FROM THE APU INLET DOOR DURING POST FLT WALKAROUND. HE SUMMONED CFR AND EXPEDITED DEPLANING.

Narrative

WHILE ENRTE TO ZZZ; WE WERE ISSUED HOLDING INSTRUCTIONS. DUE TO THE HIGH AMBIENT TEMPS AND REDUCED THRUST SETTING WHILE ENTERING THE HOLD; I (AS THE PIC) ELECTED TO START THE APU TO PROVIDE ADDITIONAL BLEED AIR FOR COOLING. AS THE PF/CAPT; I ASKED THE PNF/FO TO START THE APU. SHORTLY AFTER MY REQUEST TO START THE APU; I NOTICED THAT THE APU DOOR INHIBITOR MESSAGE HAD APPEARED ON THE EICAS AND THE APU WAS INDICATING 17% RPM. I ABORTED THE APU START BY DESELECTING THE APU START/STOP AND PWR/FUEL SWITCH LIGHTS AND WE CONTINUED TO ZZZ WITHOUT THE APU. AFTER ARR IN ZZZ DURING MY POSTFLT WALKAROUND; I NOTICED WHAT APPEARED TO BE WHITE SMOKE EXITING THE OPEN APU AIR INLET DOOR. I IMMEDIATELY RETURNED TO THE FLT DECK TO CHK FOR THE PRESENCE OF AN APU FIRE INDICATION. DEPLANING WAS STILL IN PROGRESS SO I ASKED THE FLT ATTENDANT TO EXPEDITE THE DEPLANING PROCESS. CFR WAS SUMMONED. AFTER THE PAX HAD DEPLANED THE ACFT; THE ACFT WAS SECURED; THE FDR AND CVR CIRCUIT BREAKERS WERE PULLED AND THE CREW EXITED THE ACFT AS WELL. CFR RESPONDED AND ALSO NOTED THE PRESENCE OF WHAT APPEARED TO BE WHITE SMOKE. DISPATCH WAS CONTACTED AND A MAINT WRITE-UP WAS ENTERED WITH MAINT CTL.