What was found
THE PILOT NOITCED SMOKE IN THE COCKPIT APROXIMATELY 6 MINUTES AFTER TAKEOFF. ELECTRICAL POWER WAS TURNED OFF AND THE PILOT RETURNED TO THE AIRPORT WITHOUT FURTHER INCIDENT. THE PILOT AND ONE PASSENGER WERE NOT INJURIED EXCEPT FOR A SMALL SOLDER BURN ON THE PILOT'S UPPER FOOT. INVESTIGATION DETERMINED THAT A PASSENGER SEAT BELT DAMAGED THE INFLATABLE PNEUMATIC DOOR SEAL. EXCESSIVE SEAL LEAKAGE CAUSED THE ELECTRIC PNEUMATIC PUMP TO EXCEED ITS DUTY CYCLE OVERHEATING THE PUMP VOLTAGE DROPPING RESISTORS.