On March 20, 1996, at 1500 central standard time, a Cessna 310R, N1835E, and a Piper PA-32R-300, N1030Q, collided at the intersection of runways 4 and 34 at the Marshfield Municipal Airport, Marshfield, Wisconsin. The Cessna was operating under provisions of 14 CFR Part 135 as an on demand air taxi, while the Piper was operating under 14 CFR Part 91 as a personal flight. The pilot and three passengers in the Cessna, and the pilot and one passenger in the Piper reported no injuries. Visual meteorological conditions prevailed at the time of the accident. The Cessna departed Ladysmith, Wisconsin, at 1425, and was landing on runway 34. The Piper was initiating a flight on runway 4 with the intended destination of Stambaugh, Michigan, at the time of the accident. Neither flight was operating on a flight plan. Both airplanes sustained substantial damage. The pilot of the Cessna told an inspector from the Federal Aviation Administration (FAA), that he called on the unicom frequency 123.00 MHz, his position on downwind, left base, and again on final for runway 34 at Marshfield. He further stated that he heard no call from other aircraft and observed no other traffic in the air or on the ground. He indicated that as he flared his airplane to land on runway 34, another airplane appeared from the left and a collision occurred between his airplane and the Piper in the intersection of runways 34 and 4. The pilot of the Piper told the FAA inspector that he called on the unicom frequency 123.00 MHz, reporting his intentions to back taxi on runway 4 for departure and after preparing for departure, called again to state his intentions to takeoff. He said that he did not hear any broadcast related to Marshfield. He stated that he scanned for other aircraft prior to initiating the takeoff roll, but did not see any in the air. He stated that he did not at anytime see the Cessna prior to the collision at the intersection of runway 4 and 34. Information received from the ASOS, airport personnel and the pilots involved in the accident, revealed that visual meteorological conditions prevailed at the time of the accident. The AWOS was reporting winds of 360 degrees at 15 knots, gusts to 22 knots, ten minutes prior to the accident. An examination of both airplanes subsequent to the accident revealed that the #1 and #2 communications in both airplanes were selected to 123.00 MHz. The Cessna was selected on #2 radio while the Piper was selected on #1. In a written statement a member of the airport personnel stated that he first became aware of the collision when the Cessna pilot radioed that there had been an accident. This person indicated that he did not recall hearing any prior radio communications. Although he was in a position to hear the radio, he said that he was not specifically monitoring the unicom.