On March 21, 2006, at 1040 central standard time, a single-engine Weatherly 201B agricultural airplane, N1257W, was destroyed upon impact with terrain following a loss of control while maneuvering near the Hondo Municipal Airport, near Hondo, Texas. The commercial pilot, sole occupant of the airplane, was fatally injured. The airplane was registered to Rusty's Flying Service, of Hondo, Texas, and operated by Ag Flyers Incorporated, of Hondo, Texas. No flight plan was filed and visual meteorological conditions prevailed for the local calibration flight conducted under 14 Code of Federal Regulations Part 91. According to a witness, who was also the operator's Chief Pilot, the purpose of the flight was to observe the calibration of the hopper. The pilot planned to make two passes over a field and then land. Approximately 100-gallons of water were loaded into the hopper. The pilot performed a pre-flight inspection, then started the airplane, taxied to the runway, and departed on Runway 35R. The Chief Pilot stated that after the airplane took off, it turned 180 degrees and flew along the west side of Runway 17R. The airplane then turned another 180 degrees and started the spray-run. The witness added that, "after completion of his spray pass [the pilot] pulled-up and started to turn left. I saw water being dumped from the aircraft; the aircraft pitched-up, rolled to the right and impacted the ground nose-first." The airplane came to rest in a field northwest of Runway 35L. A Federal Aviation Administration (FAA) safety inspector, who examined the airplane, reported that due to impact damage, he could not determine if there was a mechanical problem with the dump valve. However, he reported that the dump valve was found in the full open position and the stop for the handle was in a position that would keep it from being returned to the closed position. The pilot held a commercial certificate for airplane single-engine land. His most recent FAA second class medical was issued on December 14, 2005. At the time of his last physical examination, he reported a total of 325 flight hours. According to the operator, the pilot had accrued 9 hours in the accident airplane, of which 8 hours were accumulated in the 30 days preceding the accident. Weather at the airport at 0951, was reported as wind from 030 degrees at 7 knots, visibility 10 miles, temperature 60 degrees Fahrenheit, dewpoint 25 degrees Fahrenheit, and a barometric pressure setting of 30.15 inches of Mercury.