What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Flight was planned as a part 91 charity flight under instrument flight rules (IFR) from Midway airport (kmdw) to owosso community airport (krnp). The PIC was privacy data omittedflying the aircraft. The second pilot was acting as an instructor for insurance purposes (annual insurance flight had expired). Weather at 1653L was overcast at 2000 feet. The flight was cleared for takeoff on rwy 31L at kmdw. On departure, the PIC felt ?bumps? In the control wheel in the roll axis. The PIC mentioned this to the second pilot who felt the same thing in the controls. As they approached the overcast, the PIC leveled off and requested a return to the field as the bumps increased. The second pilot called for and received a turn to downwind for kmdw. The second pilot turned on the pitot heat and the circuit breaker for the right side system popped. After waiting approximately one minute the PIC pushed it in and it popped a second time. The flight declared an emergency and was given clearance to land runway 31C. While on downwind, the second pilot noticed the autopilot was on. He then asked the PIC to turn off the autopilot which he did. The aircraft landed uneventfully and requested taxi back to atlantic aviation. Approximately 500-1000 feet prior to atlantic aviation, both pilots noticed smoke coming through the defrost ducts. The PIC stopped the aircraft while the second pilot shut down electrical power. The passengers and crew evacuated the aircraft as it came to a stop at the FBO. The airport fire department opened the nose baggage compartment doors and noticed a large amount of smoke , but no fire was observed.
On the previous flight into kmdw, the circuit breaker for the cabin heat fan popped. After landing, the PIC called back to the home field and discussed the situation with the aircraft?s normal maintenance technician. After the discussion it was determined it was not required for flight under part 91 and was placarded iaw 14 CFR 91.213(d). The pilot advised the passengers that the flight from kmdw to krnp would be without heat. There were 29.2 hours of combustion heater operation since the 250 hour inspection required by AD 81-09-09 had last been performed. The last annual inspection was performed on 6/5/2015. The heater inlet duct screen had a hole in it. A significant amount of leaf debris was noted on the glare shield having come from the defrost ducting. The defrost air control was selected (pulled out). Wiring in the nose compartment near the heater was melted. Buckling of the structure that forms the nose wheel well was noted. The right side pitot-static tubing was melted. The right nose landing gear door showed evidence of heat damage.
As the FAA filed it
FLIGHT WAS PLANNED AS A PART 91 CHARITY FLIGHT UNDER INSTRUMENT FLIGHT RULES (IFR) FROM MIDWAY AIRPORT (KMDW) TO OWOSSO COMMUNITY AIRPORT (KRNP). THE PIC WAS ^PRIVACY DATA OMITTED^FLYING THE AIRCRAFT. THE SECOND PILOT WAS ACTING AS AN INSTRUCTOR FOR INSURANCE PURPOSES (ANNUAL INSURANCE FLIGHT HAD EXPIRED). WEATHER AT 1653L WAS OVERCAST AT 2000 FEET. THE FLIGHT WAS CLEARED FOR TAKEOFF ON RWY 31L AT KMDW. ON DEPARTURE, THE PIC FELT ?BUMPS? IN THE CONTROL WHEEL IN THE ROLL AXIS. THE PIC MENTIONED THIS TO THE SECOND PILOT WHO FELT THE SAME THING IN THE CONTROLS. AS THEY APPROACHED THE OVERCAST, THE PIC LEVELED OFF AND REQUESTED A RETURN TO THE FIELD AS THE BUMPS INCREASED. THE SECOND PILOT CALLED FOR AND RECEIVED A TURN TO DOWNWIND FOR KMDW. THE SECOND PILOT TURNED ON THE PITOT HEAT AND THE CIRCUIT BREAKER FOR THE RIGHT SIDE SYSTEM POPPED. AFTER WAITING APPROXIMATELY ONE MINUTE THE PIC PUSHED IT IN AND IT POPPED A SECOND TIME. THE FLIGHT DECLARED AN EMERGENCY AND WAS GIVEN CLEARANCE TO LAND RUNWAY 31C. WHILE ON DOWNWIND, THE SECOND PILOT NOTICED THE AUTOPILOT WAS ON. HE THEN ASKED THE PIC TO TURN OFF THE AUTOPILOT WHICH HE DID. THE AIRCRAFT LANDED UNEVENTFULLY AND REQUESTED TAXI BACK TO ATLANTIC AVIATION. APPROXIMATELY 500-1000 FEET PRIOR TO ATLANTIC AVIATION, BOTH PILOTS NOTICED SMOKE COMING THROUGH THE DEFROST DUCTS. THE PIC STOPPED THE AIRCRAFT WHILE THE SECOND PILOT SHUT DOWN ELECTRICAL POWER. THE PASSENGERS AND CREW EVACUATED THE AIRCRAFT AS IT CAME TO A STOP AT THE FBO. THE AIRPORT FIRE DEPARTMENT OPENED THE NOSE BAGGAGE COMPARTMENT DOORS AND NOTICED A LARGE AMOUNT OF SMOKE , BUT NO FIRE WAS OBSERVED.
ON THE PREVIOUS FLIGHT INTO KMDW, THE CIRCUIT BREAKER FOR THE CABIN HEAT FAN POPPED. AFTER LANDING, THE PIC CALLED BACK TO THE HOME FIELD AND DISCUSSED THE SITUATION WITH THE AIRCRAFT?S NORMAL MAINTENANCE TECHNICIAN. AFTER THE DISCUSSION IT WAS DETERMINED IT WAS NOT REQUIRED FOR FLIGHT UNDER PART 91 AND WAS PLACARDED IAW 14 CFR 91.213(D). THE PILOT ADVISED THE PASSENGERS THAT THE FLIGHT FROM KMDW TO KRNP WOULD BE WITHOUT HEAT. THERE WERE 29.2 HOURS OF COMBUSTION HEATER OPERATION SINCE THE 250 HOUR INSPECTION REQUIRED BY AD 81-09-09 HAD LAST BEEN PERFORMED. THE LAST ANNUAL INSPECTION WAS PERFORMED ON 6/5/2015. THE HEATER INLET DUCT SCREEN HAD A HOLE IN IT. A SIGNIFICANT AMOUNT OF LEAF DEBRIS WAS NOTED ON THE GLARE SHIELD HAVING COME FROM THE DEFROST DUCTING. THE DEFROST AIR CONTROL WAS SELECTED (PULLED OUT). WIRING IN THE NOSE COMPARTMENT NEAR THE HEATER WAS MELTED. BUCKLING OF THE STRUCTURE THAT FORMS THE NOSE WHEEL WELL WAS NOTED. THE RIGHT SIDE PITOT-STATIC TUBING WAS MELTED. THE RIGHT NOSE LANDING GEAR DOOR SHOWED EVIDENCE OF HEAT DAMAGE.