Amateur-built ZODIAC XL N601WR accident near Mountain Home, Arkansas

Probable cause

The partial loss of engine power during takeoff for reasons that could not be determined because postaccident engine examinations revealed no anomalies that would have precluded normal operation.

NTSB analysis

The pilot reported that he had recently built the airplane. The pilot operated the engine for about 4 hours, and the engine operated normally during the ground tests. During takeoff on the airplane's first flight, he advanced the throttle slowly to 2,550 rpm, and the airplane lifted off the runway about 60 mph. About three-quarters down the runway and about 50 ft above ground level, the engine began to lose power. The pilot attempted to return to the runway by turning left. The pilot completed a 180-degree left turn, but the engine rpm had reduced to about 1,925 rpm, and the airplane was unable to maintain altitude. Data from the airplane's engine monitoring device (EMD) indicated that the airplane reached a maximum airspeed of about 65 mph; the last airspeed reading before ground impact was 41 mph. The pilot attempted to land in a small clearing, but the airplane clipped a tree before landing. The airplane sustained substantial damage to the wings and fuselage during the ground impact.

Data from the EMD also indicated that the engine operated for about 12 minutes from engine start to ground impact. The data indicated that the engine oil pressure, engine oil temperature, and fuel pressure were normal throughout the flight but that the Nos. 2, 3, and 5 cylinder head temperatures exceeded 500 degrees F. A postaccident examination of the engine and carburetor revealed no evidence of mechanical malfunctions, heat distress, or failures that would have precluded the engine's operation. The reason for the increased cylinder head temperature indications and the partial power loss could not be determined.

Text from the NTSB. Open the NTSB docket for CEN15LA023 for the full record.