**This report was modified on 2/19/2014. Please see the public docket for this accident to see the original report.** On January 31, 2013, about 0845 central standard time, an Air Tractor Inc., AT-401 airplane, N9190B, impacted trees and terrain during a forced landing following an in-flight loss of engine power during agricultural application maneuvers near Victoria, Texas. The pilot was not injured. The airplane sustained substantial damage. The airplane was registered to and operated by the pilot, under the provisions of 14 Code of Federal Regulations Part 137, as an agricultural application flight. Day visual flight rules (VFR) conditions prevailed for the flight, which did not operate on a VFR flight plan. The local flight originated from a private airstrip near Victoria, Texas, about 0835. The pilot reported that he experienced a loss of engine power about eight to ten minutes into the flight. He tried various magneto switch positions and checked the magnetos where that troubleshooting did not return the lost engine power. The engine power loss worsened and the pilot executed a forced landing "in trees on flat terrain." The pilot reported that a 600-horsepower Pratt & Whitney R-1340 engine with serial number 18116 powered the airplane. He indicated that the engine had accumulated 553 hours of flight time since overhaul and 13 hours since its last inspection. A review of images acquired by a Federal Aviation Administration inspector revealed the airplane sustained substantial wing damage. A recovery company representative examined the engine when it was recovered and found the propeller was "locked" in place. The representative stated that "metal" was found in the engine oil.