BRISTOW, Oklahoma -- Federal investigators say they cannot pinpoint the cause of a plane crash that killed the owner of a Tulsa construction company and his friend.
Arthur "Allen" Couch and Tim Toppins died when their single-engine plane crashed at Jones Memorial Airport in Bristow on February 28, 2010.
According to the Probable Cause report from the National Transportation Safety Board, the cause of the crash was "the pilot's loss of control for undetermined reasons while maneuvering at low altitude."
Couch and Toppins had taken off from Jones Riverside Airport in Jenks at 1:48 p.m. that day and the crash occurred at Jones Memorial Airport in Bristow at about 2:03 p.m.
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A witness reported seeing the Hawker Beechcraft C24R circle the Bristow airport and fly low between two hangars, then hearing a loud "pop" followed by the sound of the engine sputtering.
The NTSB says the airplane hit power lines located next to the service road that runs along the runway, impacted the ground and caught fire.
The NTSB investigator found no "pre-impact anomalies" with the plane.
According to his obituary, Couch, 38, was president of W.N. Couch Inc. Contractors, a company founded by his grandfather.
Toppins, 37, worked in computers and was Couch's best friend, according to family members.
The NTSB says both men were licensed pilots and Couch had 310 flight hours and Toppins had 300.