Accident Description
On July 12, 2020, about 1110 central daylight time, a Rockwell Thrush S2R R1340, registration N3104S, was substantially damaged when it was involved in an accident near Keokuk, Iowa. The commercial pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 ferry flight.
The agricultural airplane had just completed repairs at a certified repair facility. Part of the repairs included the removal and reinstallation of both wings. The intent of the flight was to ferry the airplane cross-country from the repair station to its home base in Vinton, Iowa. A planned fuel stop was at the Keokuk Municipal Airport (EOK), Keokuk, Iowa. According to the pilot, he had topped off the airplane with 197 gallons of fuel before departing the repair station.
The pilot set up on a straight-in approach to EOK and was flying about 1,500-1,800 ft above ground level when the engine temperature surged then decreased. The engine stopped running and the pilot attempted restart procedures. The pilot determined that he was not going to make it to the airport so he decided to land the airplane in a field. During the landing, the airplane sustained substantial damage to the right wing.
Examination Findings
Examination of the airplane after the accident revealed that a rubber fuel vent line in the right wing was bent across a structural beam, kinking the line in a manner that would restrict the airflow through the line. The creased fuel vent was not related to impact damage. The installation of the right wing's vent line was improper.
Probable Cause
The National Transportation Safety Board determined that the probable cause of this accident was the improper installation of the right wing's fuel vent line, which resulted in a kinked line that restricted airflow and led to a loss of engine power.