WILLIAMSBURG, VA, USA
N776P
CESSNA 206A
DURING PREFLIGHT THE PILOT CONFIRMED 11 QUARTS OF OIL IN THE ENGINE. THE PILOT DEPARTED ON A NIGHT CROSS COUNTRY FLIGHT AND CLIMBED TO A CRUISING ALTITUDE OF 4500 FEET. FIFTEEN MINUTES AFTER TAKE OFF THE ENGINE LOST POWER. AN EXPLOSION OCCURRED IN THE ENGINE COMPARTMENT AFTER THE PILOT INITIATED A TURN TO RETURN TO THE DEPARTURE AIRPORT. THE PILOT WAS APPROACHING WATER AND ELECTED NOT TO SHUT THE ENGINE DOWN. A SECOND EXPLOSION OCCURRED FOLLOWED BY A LOSS OF OIL PRESSURE. AFTER A THIRD EXPLOSION FOLLOWED BY FIRE ERUPTING FROM THE ENGINE COMPARTMENT, THE PILOT SECURED THE ENGINE AND SHUT THE FUEL OFF. DURING THE FORCED LANDING THE LEFT WING OF THE AIRPLANE STRUCK A TREE SHORT OF THE RUNWAY, AND THE AIRPLANE CAME TO REST IN A FIELD. EXAMINATION OF THE ENGINE REVEALED THAT AN EXHAUST VALVE HAD BROKEN FREE AND CREATED A HOLE IN THE PISTON. THE ENGINE WAS FOUND ABSENT OF OIL. TWO CONNECTING RODS FAILED AT THE CRANKSHAFT JOURNALS FROM A LACK OF LUBRICATION.
On January 2, 1994, about 2223 eastern standard time, a Cessna 206A, N776P, piloted by Terry Brown, was substantially damaged during a forced landing near the Williamsburg Airport, Williamsburg, Virginia. The pilot was not injured. Visual meteorological conditions prevailed. A visual flight rules flight plan had been filed for the flight operating under 14 CFR 91. In the NTSB Form 6120.1/2, the pilot stated that during his preflight he confirmed there were 11 quarts of oil in the engine. After a long warm-up due to the cold temperature, he departed the Williamsburg Airport (JGG) and climbed to 4500 feet. About 15 minutes after take off, as he was preparing to file a flight plan, "...an instant decrease in power was noticed." He further stated: A turn was made to return to the A/P [airport] at JGG...there was an explosion from the front left side of the engine (all the flames came out there). I was approaching water...and did not want to shut down so [I] kept engine on line, 30-45 seconds later a second explosion took place, this time fire came out right front and oil pressure was lost. I still needed whatever I would get and kept the engine operating. The cockpit filled with smoke and the third explosion took place with fire coming out of the engine compartment. I secured the engine and fuel...I was not going to make the A/P, but remembered a road south west of JGG, and...set up a pattern, and landed. Evading wires on short final I dodged the tree on the right...over input left aileron and put the left wing into a tree...and ended up going backward nose-low." An engine examination was performed by a Federal Aviation Administration (FAA) Inspector and a representative of Teledyne Continental Motors on January 11, 1994, at the JGG Airport. The Teledyne representative report stated: The engine failure was induced by the failure of the #2 cylinder exhaust valve. This valve dropped into the cylinder and the severe hammering opened a hole in the piston. Combustion gases evacuated the oil through the breather and the #4 and #5 connecting rods failed at the crankshaft journals after lubrication failure. The relative damage to the connecting rods suggest the connecting rod of the #5 cylinder (right front) failed first followed by the connecting rod of the #4 cylinder (middle left)...The exhaust valve, which may have been replaced at an engine overhaul 440 hours earlier, was a Superior valve, P/N SA 6438737-7998....
an exhaust valve failure that created a hole in the piston, which allowed the complete loss of engine oil, resulting in the subsequent forced landing.
Source: NTSB Aviation Accident Database
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