What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
The pilot of N3940H experienced a rough running engine after takeoff from kbvi runway 28 that continued during the departure climb out. The pilot contacted kbvi tower to request permission to return to runway 10 due to the engine?s reduced performance. During the 180 degree turn to return to the airport, the engine stopped producing power. The aircraft settled into the tree canopy at the approach end of runway 10 and descended through the trees until contacting the ground. Neither the pilot nor his passenger was injured during the event. The aircraft was removed from the scene on September 7, via crane. On September 11, an investigation of the aircraft was performed by the allegheny flight standards district office to determine the cause of the engine?s failure to produce power. Examination found the spark plugs on the #2 and #4 cylinders to be fouled from the fuel rich mixture present in the induction system. After a cursory inspection, a cylinder compression check was performed. Cylinders #1, 2, and 4 were found to be in an airworthy condition at approximately 78/80. Cylinder #3 produced 0/80 compression. The #3 cylinder?s rocker cover was removed and it was discovered that the cylinder?s exhaust valve was stuck in the open position. The #3 cylinder was removed to further inspect the exhaust valve guide for evidence of oil coking build-up. The amount found was considered abnormal for an engine of 400 hours since overhaul. Additional investigation of the induction system showed no sign of deterioration or compromise. The fuel system was examined for debris and compromise and was found to be intact, clean, and airworthy. The engine?s ignition system was disassembled to check for condition and operational capability of the magnetos. Both magnetos were found to be airworthy and produced a strong electrical current deliverable to the spark plugs. The spark plugs were found gapped correctly showing little or no erosion, and other than the previously mentioned fouling, are in excellent condition. The exhaust system is intact and airworthy with no evidence of deterioration. The inspection found no evidence that the internal components of the engine are damaged. Crankcase, crankshaft, camshaft and valve train operate smoothly during hand propping without evidence of noise or binding. The aircraft and engine show no signs of neglect or lack of maintenance.
As the FAA filed it
THE PILOT OF N3940H EXPERIENCED A ROUGH RUNNING ENGINE AFTER TAKEOFF FROM KBVI RUNWAY 28 THAT CONTINUED DURING THE DEPARTURE CLIMB OUT. THE PILOT CONTACTED KBVI TOWER TO REQUEST PERMISSION TO RETURN TO RUNWAY 10 DUE TO THE ENGINE?S REDUCED PERFORMANCE. DURING THE 180 DEGREE TURN TO RETURN TO THE AIRPORT, THE ENGINE STOPPED PRODUCING POWER. THE AIRCRAFT SETTLED INTO THE TREE CANOPY AT THE APPROACH END OF RUNWAY 10 AND DESCENDED THROUGH THE TREES UNTIL CONTACTING THE GROUND. NEITHER THE PILOT NOR HIS PASSENGER WAS INJURED DURING THE EVENT. THE AIRCRAFT WAS REMOVED FROM THE SCENE ON SEPTEMBER 7, VIA CRANE. ON SEPTEMBER 11, AN INVESTIGATION OF THE AIRCRAFT WAS PERFORMED BY THE ALLEGHENY FLIGHT STANDARDS DISTRICT OFFICE TO DETERMINE THE CAUSE OF THE ENGINE?S FAILURE TO PRODUCE POWER. EXAMINATION FOUND THE SPARK PLUGS ON THE #2 AND #4 CYLINDERS TO BE FOULED FROM THE FUEL RICH MIXTURE PRESENT IN THE INDUCTION SYSTEM. AFTER A CURSORY INSPECTION, A CYLINDER COMPRESSION CHECK WAS PERFORMED. CYLINDERS #1, 2, AND 4 WERE FOUND TO BE IN AN AIRWORTHY CONDITION AT APPROXIMATELY 78/80. CYLINDER #3 PRODUCED 0/80 COMPRESSION. THE #3 CYLINDER?S ROCKER COVER WAS REMOVED AND IT WAS DISCOVERED THAT THE CYLINDER?S EXHAUST VALVE WAS STUCK IN THE OPEN POSITION. THE #3 CYLINDER WAS REMOVED TO FURTHER INSPECT THE EXHAUST VALVE GUIDE FOR EVIDENCE OF OIL COKING BUILD-UP. THE AMOUNT FOUND WAS CONSIDERED ABNORMAL FOR AN ENGINE OF 400 HOURS SINCE OVERHAUL. ADDITIONAL INVESTIGATION OF THE INDUCTION SYSTEM SHOWED NO SIGN OF DETERIORATION OR COMPROMISE. THE FUEL SYSTEM WAS EXAMINED FOR DEBRIS AND COMPROMISE AND WAS FOUND TO BE INTACT, CLEAN, AND AIRWORTHY. THE ENGINE?S IGNITION SYSTEM WAS DISASSEMBLED TO CHECK FOR CONDITION AND OPERATIONAL CAPABILITY OF THE MAGNETOS. BOTH MAGNETOS WERE FOUND TO BE AIRWORTHY AND PRODUCED A STRONG ELECTRICAL CURRENT DELIVERABLE TO THE SPARK PLUGS. THE SPARK PLUGS WERE FOUND GAPPED CORRECTLY SHOWING LITTLE OR NO EROSION, AND OTHER THAN THE PREVIOUSLY MENTIONED FOULING, ARE IN EXCELLENT CONDITION. THE EXHAUST SYSTEM IS INTACT AND AIRWORTHY WITH NO EVIDENCE OF DETERIORATION. THE INSPECTION FOUND NO EVIDENCE THAT THE INTERNAL COMPONENTS OF THE ENGINE ARE DAMAGED. CRANKCASE, CRANKSHAFT, CAMSHAFT AND VALVE TRAIN OPERATE SMOOTHLY DURING HAND PROPPING WITHOUT EVIDENCE OF NOISE OR BINDING. THE AIRCRAFT AND ENGINE SHOW NO SIGNS OF NEGLECT OR LACK OF MAINTENANCE.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.