NTSB Identification: LAX01LA108.
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Accident occurred Sunday, March 04, 2001 in Marana, AZ
Probable Cause Approval Date: 07/30/2001
Aircraft: Harlow Lancair ES, registration: N350N
Injuries: 1 Minor,1 Uninjured.

NTSB investigators may have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

During cruise flight the pilot noted smoke coming from the engine cowling. He initiated a precautionary landing at an airport along his route of flight. When the pilot added power to adjust his glide path, he noticed that the engine was responding to throttle input, but the propeller was not. The pilot stated that when he realized he could not make the airport, he directed the airplane to a plowed agricultural field. During the landing sequence, the nose gear "dug in" and collapsed; the airplane was nosed over. The airplane came to rest inverted. The pilot, who is also the builder of the airplane, noted that the propeller drive belt pulley had been heated and distorted, and the drive belt had separated. He also noted what appeared to be spots of molten aluminum near the drive pulley. The pilot stated that the reduction drive bearing and belt had failed for unknown reasons. The FAA approved manufacturer of this particular airplane kit stated that they do not support the use of non-aviation applications, equipment or hardware on the airplane designs they offer. The manuals and plans provided with the kit call for Continental or Lycoming engines only. The accident airplane used a marine version of the General Motors LT-1 350 automotive engine with a non certified V-belt reduction drive unit.

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

Failure of the propeller reduction drive unit which resulted in drive belt and pulley failure and a subsequent loss of thrust requiring an emergency landing on soft terrain. The reason for the bearing and/or belt failure was not determined. A factor was the loss of propeller thrust, which precluded the pilot from maintaining the proper glide path to the runway.

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