NTSB Factual Report

On November 23, 2002, at 1610 central standard time, an amateur-built Woods Velocity, N241KW, sustained substantial damage during a forced landing to a wheat field near Claflin, Kansas, after a total loss of engine power. The commercial pilot was not injured. The 14 CFR Part 91 test flight departed Ellsworth Municipal Airport (9K7), Ellsworth, Kansas, at 1540 on a local test flight. Visual meteorological conditions prevailed. No flight plan was filed.

The pilot reported the takeoff and climb to 1,500 feet above ground level (agl) was normal. He reported that when he was in a subsequent climb the oil temperature started to go into the "yellow," but it stabilized when he increased airspeed and established a cruise power setting. After about five minutes, the oil temperature went into the yellow arc again and briefly reached red line, 230 degrees F. The pilot reduced power and the oil temperature went back into the green arc. The pilot reported that whenever he attempted to climb, the oil temperature would climb into the yellow arc. The pilot reported, "Within a few minutes the engine quit with no warning." The pilot executed a gear up forced landing to a wheat field.

The pilot reported that the engine problems started when he was about 15 miles from 9K7. He elected to fly toward Great Bend (GBD), Kansas, which was about 20 miles away. He reported that there was a 20 knot tailwind if he headed toward GBD, and he reported that the approaches to GBD were unobstructed, unlike the approaches at 9K7.

The amateur-built Woods Velocity was powered by a Mazda rotary engine that was converted for aviation use by Powersport Aviation. The engine model was 215 horsepower Powersport RE-215, serial #2. The engine was equipped with a data computer that recorded the engine operating parameters of the accident flight. The airplane and engine had about 5 hours of flight time at the time of the accident. The accident flight was the 10th test flight of the airplane.

The engine data collection computer recorded the following information:

1. The flight was 11 minutes and 49 seconds in duration. (takeoff to landing).

2. At about 11 minutes into the flight, the rpm dropped from 5,488 to 4985 for 1 second.

3. 5 seconds after this "stumble" the rpm dropped to 3,903.

4. 16 seconds after power loss, the rpm was 3323. The pilot increased throttle from site 11.4 (of 15) to 13.5.

5. 32 seconds after power loss, the rpm was 3092. The pilot increased throttle setting to site 15 (full).

6. The pilot brought the throttle back to idle 46 seconds after power loss, or 4 seconds before the rpm registered zero.

7. The oil temperature was 220 degrees F. at the time of power loss.

8. The water temperature was 187 degrees F. at the time of power loss.

9. Total "glide" time is estimated to be 45 to 49 seconds.

The airplane's builder and a representative of Powersport Aviation inspected the airplane. The Powersport Aviation's inspection report stated the following:

"The exhaust was cracked/broken in two places. There was a 360 degree fracture at the rotor #1 engine flange separating the pipe from the engine, and a fracture where the two primary pipes merge to one in the augmenter.

The exhaust heat shield had several cracked tack welds, but no missing pieces.

The inspection revealed evidence of extreme heat in the following areas:

1. Blistered paint on the lower cowling near the engine mount.

2. Badly deformed starboard side engine vibration isolators.

3. Burned paint and carbonized epoxy on the engine housings.

4. Discolored fastening bolts.

5. Carbonized/charred water pump suction hose.

6. Melted wire insulation on customer installed micro-switch that was mounted on throttle cable.

7. Excessively shrunk shrink-wrap on fuel injector wire harness connectors.

8. "Stiff" electrical harness on exhaust side of engine."

The inspection of the airframe and engine revealed no pre-existing anomalies. An engine run was conducted and the engine operated within normal operating parameters.

The inspection revealed that, "There were many indications of excessive heat around the fuel system, heat which may have been over 400 degrees F." The representative of Powersport Aviation recommended that, "all engine integrations incorporate some kind of temperature probe or alarm system placed in the vicinity of the exhaust to warn of potential danger. The exhaust systems must also be designed and built to accommodate the differential expansion of each primary pipe, and be mounted so that no external forces affect its operation." (See Powersport Aviation's "Kerry Wood's Velocity Crash Factual Report N241KW)

Parties to the investigation included the Federal Aviation Administration and Powersport Aviation.

NTSB Probable Cause

The total loss of engine power while in cruise flight due to vapor lock of the fuel line as a result of the fractured exhaust manifold. A factor was the unsuitable terrain encountered during the forced landing.