Cessna 402/402C/B379 Businessliner/Utiliner
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Ground Event / Encounter Other / Unknown
Aircraft Aircraft Damaged; Flight Crew Returned To Gate; General Evacuated; General Declared Emergency
Aircraft; Human Factors
We were inbound for landing at our destination. The [cabin] heater; which was working poorly and had a poor smell the entire flight; had completely stopped working about 10 miles from the runway. I shut it off and closed the vents to try and keep as much warmth in inside as possible. On the taxi in I decided to test the heater one more time before reaching the ramp.  It still didn't seem to work. As I reached the parking spot I shut the engines down and my co-pilot said; 'It's smoking; the heater is smoking.' I [then] saw smoke coming out of the defrost vents.I immediately climbed back towards the door and opened it for the passengers and told them to get off the plane. I pointed to a sign in the distance for them to go to.  The Ops agents called the fire trucks [but] there didn't seem to be flames anywhere visible. If I were to do this all over again I would probably not have tested the heater one more time.  I should have just written it up as soon as we were got to the gate.
The flight crew of a CE-402 shut down the cabin heater enroute due to smoke and poor heating.  After landing the Captain opted to test it while taxiing to the gate.  Shortly after the First Officer noted it was smoking.  They evacuated the passengers and a ground agent called for CFR. The Captain opined afterward that; given similar circumstances; would be unlikely to perform a test subsequent to having turned it off for cause.