NTSB Identification: FTW04LA124.
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Accident occurred Saturday, May 08, 2004 in Fort Stockton, TX
Probable Cause Approval Date: 09/29/2004
Aircraft: Aeronca 7AC, registration: N3708E
Injuries: 2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The 821-hour commercial pilot lost engine power while in cruise flight at 2,500 feet mean sea level approximately 25 miles west of his intended destination. While en route, he noticed the oil temperature gauge indicated 240 degrees (red line was 145 degrees). The pilot reduced engine rpm from 2,400 to 2,200, and increased the airplane's mixture setting. The oil temperature began to decrease. Shortly after, the engine suddenly began to lose power. The pilot increased the mixture setting to "full rich", and applied carburetor heat, but the engine continued to lose power. He was unable to maintain altitude and executed a forced landing to a service road on Interstate 10. Upon landing, the pilot was unable to keep the airplane straight due to the strong, gusting crosswinds and collided with a metal fence post and mesquite trees. Examination of the top and bottom spark plugs revealed the #2 and #4 plugs were oily, and the #1 and #3 plugs appeared white in color. The oil, which was changed approximately 8 hours before the accident, was dark in color. When asked how this accident could have been prevented, the pilot reported, "I probably leaned engine too much too long causing the oil temp[erature] to reach 240 degrees. Run aircraft more rich to provide better cooling to internal combustion chambers." Weather reported at an airport about 17 miles from the accident site were reported as wind from 130 degrees at 17 knots gusting to 24 knots.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's improper leaning of the fuel/air mixture in-flight, which resulted in a loss of engine power. Factor were the wind gusts and the crosswind.

Full narrative available

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