Primary finding
Probable cause
Blockage of the oil scavenge pump by foreign material which was introduced into the engine during maintenance. A factor was the lack of suitable terrain for the forced landing.
Investigator assessment
Analysis narrative
While on a cross country flight, the engine lost power and a forced landing was conducted. During the approach, the aircraft struck power lines. Examination of the engine provided evidence of oil sump contamination in the form of a paper towel appearing item. This plugged the oil pick up and caused oil starvation. Evidence indicates the piece of paper towel appearing material may have been introduced into the engine during maintenance to a cylinder a short time prior to the trip originating.
Source record
Factual narrative
On June 19, 1994, at 1130 mountain daylight time, a homebuilt Varieze, N111DR, struck power lines while conducting a forced landing due to a loss of power 2 miles west of Fort Lupton, Colorado. The pilot sustained serious injuries and his passenger minor injuries. The aircraft was destroyed. Visual meteorological conditions prevailed and no flight plan was filed. The flight departed Olathe Kansas, at 0800 with an intended destination of Longmont, Colorado. According to the pilot, he was in cruise flight when the engine lost oil pressure and a total loss of power occurred. He said he attempted to land on a highway but struck a power line during approach. Examination of the engine provided evidence of a large piece of paper towel appearing material in the oil sump. This piece of material had plugged the oil pick up resulting in oil starvation to the engine. Available information indicates the engine had maintenance performed on a cylinder a short time prior to this trip and that the piece of material may have been introduced into the engine at that time. -