LAFAYETTE, LA, USA
N4803U
Cessna TU206G
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.
On November 17, 1999, at 1140 central standard time, a Cessna TU206G airplane, N4803U, was substantially damaged during a forced landing following a loss of engine power while in cruise flight near Lafayette, Louisiana. The airplane was owned and operated by Gulf Coast Aerial Mapping Co. of Baton Rouge, Louisiana. The commercial pilot and photographer/crewmember were not injured. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 aerial photography flight. The flight originated from Baton Rouge, Louisiana, at 1015. During a telephone interview conducted by the NTSB investigator-in-charge, the pilot stated that they departed Baton Rouge and flew to Lake Charles, Louisiana, to conduct aerial photography. During the return flight, while at 3,500 feet msl, the pilot noticed the "engine noise get quieter." The pilot looked at the manifold pressure gauge and noted that he had "lost about 5-6 inches of pressure." He stated that he thought that the throttle control had slipped aft; however, the engine RPM was exceeding its red line limit. At about the same time, the cameraman directed the pilot's attention to the oil pressure gauge, which was indicating zero. The pilot contacted Lafayette Approach Control and stated he needed to make a precautionary landing, and they cleared him to land at Lafayette. During this time there was a total loss of engine power, and the pilot reported to Lafayette Approach Control that he was going to attempt a forced landing to a field. In the enclosed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the pilot stated that he misjudged the approach and was too high and too fast. The pilot provided an annotated photograph of the field, which indicated that he landed with a tailwind and overshot his intended field. During the forced landing, the airplane went through a barbed wire fence resulting in the nose and right main landing gear collapsing. According to an FAA inspector, who visited the accident site, the empennage, elevator, and wings sustained structural damage. On February 8, 2000, an FAA inspector, along with a representative from Teledyne Continental Motors, examined the TSIO-520-HCM engine (serial number 506251). A crack was observed in the right side of the crankcase near the right magneto. Disassembly of the engine revealed that the #1 connecting rod had 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." The other crankpins were also "very dry." The crankshaft journals had moderate scoring and were coated with oil. Inspection of 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. Internal impact damage precluded any further examination of the failed parts. The engine underwent its last 100-hour inspection on November 1, 1999, at an engine total time and time since major overhaul of 2,918.7 hours and 1,324.6 hours respectively.
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.
Source: NTSB Aviation Accident Database
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