On September 10, 1998, at 1910 central daylight time (cdt), a WSK-PZL Meilec PZL M18B, N4450M, operated by a commercial pilot, was destroyed when just after takeoff the airplane impacted into a swamp. Visual meteorological conditions prevailed at the time of the accident. The aerial application flight was being conducted under 14 CFR Part 137. There was no flight plan on file. The pilot reported no injuries. The local flight was originating at a private airstrip 3 and 1/2 miles north of Tappen, North Dakota. In his written statement, the pilot said that the airplane lifted off normally, but then wanted to set back down. The pilot lowered the flaps to 15-degrees in hopes of keeping the airplane from settling. Lowering flaps did not seem to help. The pilot said that he then went for the dump handle, but could not find it initially. When he did find it, the airplane impacted the ground. A Federal Aviation Administration (FAA) inspector examined the airplane at the scene. The airplane was resting upright in a swamp off the end of a 3,000 foot long airstrip. The right wing was curled up. The left wing was bent upward at the root, approximately 45 degrees. The airplane's fuselage was broken into three pieces. The propeller showed torsional bending and chordwise scratches. Flight control continuity was confirmed. No anomalies were found with the engine, engine controls, or other airplane systems. According to the Takeoff Distance Chart in the PZL M18B Aircraft Flight Manual, an airplane with atomizers and zero flaps extended, weighing 10,700 pounds, at a temperature of 33 degrees Centigrade, and zero headwind, will require a takeoff distance of approximately 3,600 feet.