CHALLENGER II N441MS accident near St. Joesph, Illinois

Probable cause

The total loss of engine power due to a lack of lubrication following the in-flight failure of the mechanical oil injection pump. Contributing to the accident was the temporary obscuration of the pilot's forward visibility due to sun glare during the forced landing, which resulted in a collision with power lines.

NTSB analysis

The pilot reported that, during cruise flight about 1,200 ft mean sea level, the engine experienced a sudden and total loss of power. He was unsuccessful in reestablishing engine power and selected a nearby soybean field for a forced landing. The pilot stated that, as he maneuvered the airplane toward the field, the setting sun temporarily obstructed his forward visibility. The airplane subsequently collided with power lines and then entered an aerodynamic stall and impacted terrain.

A postaccident engine examination revealed scoring and a lack of proper oil lubrication of the forward cylinder piston adjacent to the intake and exhaust ports. The rear cylinder piston did not exhibit scoring; however, evidence of oil starvation was observed. Further examination of the oil system revealed that the mechanical oil injection pump had seized within its housing. Additionally, the oil pump nylon drive-coupling had fractured. The oil pump was a nonserviceable component that prevented further disassembly. The pilot reported that the experimental engine was not originally equipped with a mechanical oil injection pump and that he had the engine modified with the oil pump about 50 hours before the accident. The total loss of engine power during the accident flight was due to a cylinder seizure, which resulted from a lack of lubrication following the failure of the mechanical oil injection pump.

Text from the NTSB. Open the NTSB docket for CEN14LA309 for the full record.