Authorities in southwest Iowa have identified the man who was killed over the weekend when the experimental aircraft he was flying crashed. Cass County Sheriff Bill Sage says the 39-year-old pilot, Stephen Merk of Wiota, died Saturday morning less than a mile from the Anita Airport south of the Anita State Park dam. Sage says the type of plane Merk was flying had not yet officially been rated by the F-A-A. The wreckage of the red-and-white aircraft was removed from the scene of the crash Saturday afternoon. It was taken to an undisclosed location for examination. Sage says a witness to the accident heard the plane’s engine sputter twice before the craft spiraled into the ground. He says they’re not sure whether the plane stalled.The plane left the Anita airport on an apparent test flight and was making its return when the problems with the engine began. Sage says the F-A-A investigation into what caused the crash will likely take three months. The last fatal airplane crash in Cass County occurred in 1989, when two State Troopers were killed South of Atlantic.