On June 19, 1995, at 0927 central daylight time, a Cessna A188B, N53372, collided with N9433R, a Cessna A188B, while both airplanes were on approach near Weslaco, Texas. N53372 was substantially damaged and N9433R sustained minor damage. Neither of the commercial pilots was injured. Both airplanes were operated by Stanley Flying Service under Title 14 CFR Part 137. No flight plans were filed and visual meteorological conditions prevailed for the aerial application flights which departed Weslaco at 0655 CDT. Both airplanes were returning to land on runway 13 at the Mid Valley Airport after working in the same general area. According to the pilot of N9433R, he entered the traffic pattern on a left base 2 to 3 miles northeast of the airport, turned final and began descending. He reported looking up and to the left and seeing N53372 "a split second before impact." According to the pilot of N53372, he entered the traffic pattern at midfield on a left downwind, turned base and then final "approximately 1/4 mile from the approach end of the runway." Both pilots submitted sketches indicating that the collision occurred immediately after N53372 turned final. A witness interviewed by the Weslaco Police Department stated that "when she saw the airplanes they were flying close to each other and that the yellow airplane [N9433R] flew upward and struck the other red and blue plane [N53372]." Following the collision, both airplanes continued to the airport and landed without further incident. Examination of the airplanes by a Federal Aviation Administration (FAA) inspector revealed that the left wing tip of N9433R was separated, and there was minor damage to the left wing leading edge and the left aileron. The right side of the fuselage of N53372 was torn open aft of the cockpit. The FAA inspector further reported that N9433R was equipped with a business band radio, while N53372 had a VHF aircraft radio installed.