On May 30, 2000, at 1330 central daylight time, a Pzl-Mielec M-18A agricultural airplane, N2065S, sustained substantial damage during an in flight collision with terrain while maneuvering near Marmaduke, Arkansas. The commercial pilot, sole occupant of the airplane, sustained minor injuries. The airplane was registered to a private individual and operated by Sky King Aviation, Inc., of Rector, Arkansas. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 137 aerial application flight. No flight plan was filed for the local flight that departed from the Rector Airport approximately 1305. In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the pilot reported that the airplane "had a violent vibration" while in a turn. The pilot leveled the wings, pitched the nose down, and added power. He then flew the airplane straight and level for 1.5 miles. As the pilot banked the airplane right to turn back into the wind, the airplane began descending. The pilot added more power, but the airplane continued to descend. Although the pilot executed an emergency hopper dump and added full power, the airplane descended into a cotton field. The right main landing gear touched the ground, and the airplane began skidding across the field. After passing under power lines and across a highway, the airplane began to climb. Subsequently, the airplane impacted trees and came to rest in a near vertical attitude against a tree. The pilot did not report any mechanical anomalies with the aircraft.