Accident Cessna TU206G N4803U, Wednesday 17 November 1999

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Date:	Wednesday 17 November 1999
Time:	12:40 LT
Type:	Cessna TU206G
Owner/operator:	Gulf Coast Aerial Mapping Co.
Registration:	N4803U
MSN:	U20605109
Year of manufacture:	1979
Total airframe hrs:	8860 hours
Engine model:	Continental TSIO-520-HCM
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	Substantial
Category:	Accident
Location:	Lafayette, LA - United States of America
Phase:	En route
Nature:	Unknown
Departure airport:	Baton Rouge, LA (BTR
Destination airport:
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
During an aerial photography flight, at 3,500 feet msl, the pilot noticed the 'engine noise get quieter,' and the engine lost approximately 5-6 inches of manifold pressure. The photographer/crewmember noticed that the oil pressure gauge was indicating zero. The pilot initially planned on making a precautionary landing at an airport; however, the engine experienced a total loss of power, so the pilot set up for a forced landing in a field. The pilot reported that he misjudged the approach and was too high and too fast. The pilot added that he landed with a tailwind and overshot his intended field, and the airplane went through a barbed wire fence. During a post-accident examination of the engine, it was found that the #1 connecting rod failed near the connecting rod cap. The #1 crankpin had the connecting rod cap bearing melted into the surface, and the surface appeared very dry and discolored. Inspection of all the rod cap bearings revealed that they were reddish brown in color, indicating that there was a lack of oil supply through the oil galley of the engine. The oil pump was found intact, free to rotate, and the gears were coated with oil.

Probable Cause: The partial blockage of oil within the engine's oil galley resulting in a total power loss. Contributing factors were the failure of the #1 connecting rod, the failure of the pilot to achieve the proper touchdown point during the forced landing, the tailwind and the fence.

Accident investigation: