Amateur-built VARIEZE N80681 accident near Santa Paula, California

Probable cause

A total loss of engine power due to fatigue failure of the camshaft drive gear teeth.

NTSB analysis

The airline transport pilot and a passenger departed on a local area flight; shortly after takeoff, the engine experienced a total loss of power. To the northwest of the accident site was an open field and a road; both were available to use for landing but presented challenges. The field had been recently plowed and there was auto traffic on the road. It was likely that the pilot was attempting to land on the road but struck power lines during the descent. The airplane came to rest in a lemon orchard and was subsequently consumed by a postcrash fire.

Visual examination of the engine revealed thermal damage. The engine crankcase was disassembled; the main bearings on the left crankcase half were dark in color and exhibited pitting. The camshaft drive gear cluster displayed nine broken teeth, most of which were found in the oil sump.

Metallurgical examination revealed that three of the camshaft drive gear teeth failed in fatigue, which subsequently resulted in the overstress failure of the other six teeth. The fatigue initiated at sharp corners formed during hand-grinding of the forward faces of the teeth while dressing the edges and removing burrs from the teeth during manufacture.

Airplane logbook entries revealed that the engine was assembled by a third party and installed new on the airframe about 13 years before the accident.

Text from the NTSB. Open the NTSB docket for WPR16FA118 for the full record.