On May 21, 2004, at 0815 central daylight time, an Air Tractor AT-301 single-engine tailwheel-equipped agricultural airplane, N3168H, registered to and operated by Moad Aviation Inc., of Weslaco, Texas, was substantially damaged when it struck a power line and impacted the ground during an aerial application flight near Donna, Texas. The commercial pilot, sole occupant of the airplane, sustained minor injuries. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from a private airstrip, near Donna, Texas, at 0740. The 4,300-hour pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that he had been performing an aerial application on a field using a "squeeze" pattern, starting from the outside of the field moving inwards to the middle. After approximately three-quarters of the field had been sprayed, the pilot changed directions and initiated an entry to the field from another direction. As the pilot was flying downwind under three electrical power lines, the airplane struck two of the lines. Subsequently, the airplane impacted the ground approximately 50 feet from the power lines, and came to rest upright approximately 125 feet from the initial point of impact. Examination of the airplane by the pilot revealed the top portion of the vertical stabilizer and rudder were sheered off. The engine and both main landing gears were separated from the fuselage. Both power lines were severed. The pilot stated in the NTSB Form 6120.1/2 that in-flight visibility was greater than 10 statute miles, wind from the southeast at 8 knots, with a broken layer of clouds at 2,000 feet above ground level.