NTSB Identification: DEN07LA133.
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Accident occurred Wednesday, August 01, 2007 in Sylvan Grove, KS
Probable Cause Approval Date: 12/20/2007
Aircraft: Walker Lancair IV, registration: N7441W
Injuries: 1 Serious.

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 airplane had been fully serviced with fuel and oil prior to takeoff. During the initial climb to 10,500 feet, the electronic manifold pressure gauge malfunctioned so the pilot managed power "by throttle position." He reduced power when the number 2 cylinder head temperature increased more than the other cylinder head temperatures. Almost immediately upon leveling off, the engine lost power. When the fuel boost pump was switched to HIGH, the engine "fired and achieved lower power for 30 seconds." Mixture control manipulation restarted the engine, but after a few seconds there was "an explosion and a lot of smoke." The engine stopped but [the propeller] "appeared to be turning freely" all the way down. The pilot made a rapid descent and landed in an open field. The airplane rolled about 400 feet, crested a small rise, then struck a ground depression that collapsed the landing gear. The airplane then slid sideways for another 300 feet. The pilot used his cellular telephone to alert authorities of the accident. FAA inspectors examined the engine, a Continental TSIO-550-B-1-B (s.n. 802008), and found evidence of catastrophic engine failure. An oil line to the turbocharger wastegate actuator had come loose, causing oil starvation and high heat distress. A hole in the engine case exposed the number 5 journal and imprints from rod bolt strikes. The airplane was built in 1992. The engine had a total time of 88 hours.

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

A catastrophic engine failure due to oil starvation when an oil line to the turbocharger wastegate actuator came loose. Contributing factors in this accident were the unsuitable terrain on which to make a forced landing.

Full narrative available

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