Nanchang China CJ 6 N8NW accident near Buckeye, Arizona

Probable cause

The failure of the fuel pump’s diaphragm which resulted in fuel system contamination from air and or oil and caused the engine to lose power.

NTSB analysis

The pilot and passenger onboard the experimental airplane were descending toward the destination at the conclusion of a cross-county flight when the engine rpm began to vary and the engine eventually lost power. The pilot initiated a forced landing to a clearing at a nearby construction site, during which the left wing impacted an obstacle, resulting in substantial damage.

Postaccident examination of the engine revealed that the fuel pump’s diaphragm, located on the drive shaft, was ruptured. The diaphragm was designed to prevent fuel system contamination. Remnants of the diaphragm were observed on the accessory side of the pump and the diaphragm was located inward from its original position on the drive shaft. It is likely that this ruptured diaphragm caused the fuel system to be contaminated with air and or oil and resulted in the loss of power to the engine. No other mechanical anomalies were revealed that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR18LA006 for the full record.