What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) On sept. 17, 2004, the owner altered the engine cooling system by moving the radiator approx. 4" aft of it's original location, away from the engine exhaust system after noting higher than normal (190-200 deg. F) engine operating temperature. This alteration increased the cooling system fluid capacity by lengthening the radiator hoses. It should be noted that upon servicing the cooling system the owner was unable to return all coolant removed having approx. 1 quart remaining. This cooling system modification was at the advice of the airframe manufacturer however, the owner is not a mechanic and did not have the required cooling system service instructions on hand at the time for this make and model. On sept. 18, 2004 the owner performed an inspection of all engine spark plugs (4 ea.) Having difficulty installing the left hand forward plug due to fouled threads, the owner replaced this spark plug with an autolite p/n APP3923, the remainder of the gyrocopters spark plugs is l/h aft cylinder-bosch p/n FR8DPX, r/h fwd and aft cylinders-champion p/n RC10YP. The owner then performed a 30-40 minute ground run and leak check-with cooler (140 deg f) engine operating temperature noted and no cooling system leaks. At this point the owner/operator requested and received approval to depart Pontiac airport (ptk) in clear, calm, day VMC conditions. Shortly after departure from runway 27R to the west at an altitude of 200 feet the operator experienced low power output from the single powerplant with no associated instrument indications. The operator declared an emergency and returned to ptk in an easterly direction and once clearing the airport perimeter fence, landed the aircraft at the west end of the airport in the grassy area at the end of runway 27R at a high sink rate causing substantial damage to the airframe structure and propellers. FAA FSDO investigation of the fuel, fuel filters, fuel pumps and carburetor linkage found no apparent defects. A compression test was performed with both aft cylinders exhibiting little compression capability. Upon visual/borescope inspection of all cylinders found both aft cylinders exhibiting evidence of scoring and overheating. privacy data omitted
As the FAA filed it
(-23) ON SEPT. 17, 2004, THE OWNER ALTERED THE ENGINE COOLING SYSTEM BY MOVING THE RADIATOR APPROX. 4" AFT OF IT'S ORIGINAL LOCATION, AWAY FROM THE ENGINE EXHAUST SYSTEM AFTER NOTING HIGHER THAN NORMAL (190-200 DEG. F) ENGINE OPERATING TEMPERATURE. THIS ALTERATION INCREASED THE COOLING SYSTEM FLUID CAPACITY BY LENGTHENING THE RADIATOR HOSES. IT SHOULD BE NOTED THAT UPON SERVICING THE COOLING SYSTEM THE OWNER WAS UNABLE TO RETURN ALL COOLANT REMOVED HAVING APPROX. 1 QUART REMAINING. THIS COOLING SYSTEM MODIFICATION WAS AT THE ADVICE OF THE AIRFRAME MANUFACTURER HOWEVER, THE OWNER IS NOT A MECHANIC AND DID NOT HAVE THE REQUIRED COOLING SYSTEM SERVICE INSTRUCTIONS ON HAND AT THE TIME FOR THIS MAKE AND MODEL. ON SEPT. 18, 2004 THE OWNER PERFORMED AN INSPECTION OF ALL ENGINE SPARK PLUGS (4 EA.) HAVING DIFFICULTY INSTALLING THE LEFT HAND FORWARD PLUG DUE TO FOULED THREADS, THE OWNER REPLACED THIS SPARK PLUG WITH AN AUTOLITE P/N APP3923, THE REMAINDER OF THE GYROCOPTERS SPARK PLUGS IS L/H AFT CYLINDER-BOSCH P/N FR8DPX, R/H FWD AND AFT CYLINDERS-CHAMPION P/N RC10YP. THE OWNER THEN PERFORMED A 30-40 MINUTE GROUND RUN AND LEAK CHECK-WITH COOLER (140 DEG F) ENGINE OPERATING TEMPERATURE NOTED AND NO COOLING SYSTEM LEAKS. AT THIS POINT THE OWNER/OPERATOR REQUESTED AND RECEIVED APPROVAL TO DEPART PONTIAC AIRPORT (PTK) IN CLEAR, CALM, DAY VMC CONDITIONS. SHORTLY AFTER DEPARTURE FROM RUNWAY 27R TO THE WEST AT AN ALTITUDE OF 200 FEET THE OPERATOR EXPERIENCED LOW POWER OUTPUT FROM THE SINGLE POWERPLANT WITH NO ASSOCIATED INSTRUMENT INDICATIONS. THE OPERATOR DECLARED AN EMERGENCY AND RETURNED TO PTK IN AN EASTERLY DIRECTION AND ONCE CLEARING THE AIRPORT PERIMETER FENCE, LANDED THE AIRCRAFT AT THE WEST END OF THE AIRPORT IN THE GRASSY AREA AT THE END OF RUNWAY 27R AT A HIGH SINK RATE CAUSING SUBSTANTIAL DAMAGE TO THE AIRFRAME STRUCTURE AND PROPELLERS. FAA FSDO INVESTIGATION OF THE FUEL, FUEL FILTERS, FUEL PUMPS AND CARBURETOR LINKAGE FOUND NO APPARENT DEFECTS. A COMPRESSION TEST WAS PERFORMED WITH BOTH AFT CYLINDERS EXHIBITING LITTLE COMPRESSION CAPABILITY. UPON VISUAL/BORESCOPE INSPECTION OF ALL CYLINDERS FOUND BOTH AFT CYLINDERS EXHIBITING EVIDENCE OF SCORING AND OVERHEATING. ^PRIVACY DATA OMITTED^