What happened
During flight, the pilot observed oil accumulating on the windscreen. He continued to the destination and landed on runway 16 with an oil-covered windscreen in what he described as "squirrely winds." The wind was estimated to be from 150 degrees at 15 knots gusting to 22 knots with light turbulence. During the landing roll, the pilot lost control of the aircraft in the unfavorable wind conditions while his forward visibility was restricted. The aircraft ground looped and ran off the left side of the runway.
The investigation
An examination of the aircraft revealed that the oil filler extension tube had separated from the engine case. The pilot stated that a similar type of problem occurred in May 1979 and that the maintenance personnel had epoxied the oil filler extension tube back into the engine.
Findings
The oil-covered windscreen restricted forward visibility during the landing roll. Contributing to the loss of control were the unfavorable wind conditions, including gusts up to 22 knots and light turbulence, which made maintaining directional control difficult. The previous repair method for the oil filler extension tube may have contributed to its separation.