America Airlines Convair N94263 departed Dayton for Columbus at 19:52. At 20:07 the flight contacted Columbus tower while 6 miles west of the Hilliard fan marker (12 miles W of the airport). The tower approved a requested right traffic pattern to runway 27. The downwind leg was flown at 1200 feet with a 160 knots airspeed and 16deg flaps. The Convair crew were given a landing sequence of number 2 following a TWA Martin which was making a straight-in approach to runway 27. In order to establish a normal interval behind the Martin the first officer extended the downwind leg a little. He then began a descending right turn for the approach to the runway, which was completed at 850 feet above the ground and 3,5 miles short of the runway. When about 0,6 miles short of the threshold and about 300 feet above the ground the crew felt a violent jar and simultaneous yaw to the left. The left engine had stopped and the crew realigned the plane with the runway and landed. During the landing roll the nose gear collapsed. It appeared that the plane had collided with a US Navy Beech SNB-2C Navigator (23773). The Beechcraft crashed and burned. PROBABLE CAUSE: “A traffic control situation created by the tower local controller which he allowed to continue without taking the necessary corrective action. A contributing factor was the failure of both crews to detect this situation by visual and/or aural vigilance.”