Accident Overview
On July 22, 2020, at about 1745 central daylight time, a Vans RV4, registration N54WP, was substantially damaged in an accident near Idabel, Oklahoma. The airline transport pilot and a child passenger were not injured. The airplane was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Sequence of Events
According to the pilot, he was on a multi-leg cross-country flight. During a planned refueling stop at Kennett Memorial Airport (TKX) in Kennett, Missouri, the pilot noticed an oil leak from a chaffed oil line leading to the propeller governor. With assistance from a local fixed base operator mechanic, the damaged oil line was removed and replaced with a used serviceable oil line. After installation and preflight, the pilot departed and climbed to 5,500 ft mean sea level en route to his destination.
About 70 minutes later, the pilot smelled something and observed oil on the windscreen. He asked air traffic control for the nearest airport, which was about 11 miles away. While maneuvering to the airport, the engine stopped producing power. About 1/2 mile from the airport and approximately 70 ft above the ground, the pilot attempted to land on a roadway. The airplane impacted power lines and then the ground. The pilot stated that he could not see the power lines through the oil-covered windscreen. The airplane came to rest in a ditch adjacent to the roadway, resulting in structural damage to the fuselage and empennage. Both occupants exited the airplane uninjured.
Post-Accident Examination
Examination of the engine after the accident revealed a crack in the oil line leading to the propeller governor from its connection at the engine case. There was no clamp installed to secure the line.
Airworthiness Directive
The experimental airplane had a conditional airworthiness inspection on May 1, 2020. According to Federal Aviation Administration Airworthiness Directive (AD) 90-04-06R1, a clamp should have been installed on the oil line leading to the propeller governor. The pilot reported that when he replaced the oil line at TKX, there was no clamp present, so he did not install a clamp and was not aware of the applicable AD. He also reported that had he been aware of the AD, he would have installed a new oil line and clamp.