At about 14:50 EST, a Cessna 172P and a Cessna 172R collided in flight on approach to Fitchburg Municipal Airport. The pilot of the 172P was killed and the student pilot in the 172R suffered serious injuries. According to several witnesses, the airplanes were on the final approach segment to the airport when the student pilots airplane overtook the private pilots airplane and struck it on the right side. The two airplanes locked together and made a slow, 180-degree turn while descending rapidly to the ground about 2,000 feet from the approach end of runway 32. The left landing gear strut of the student pilots airplane was embedded in the right side of the private pilots airplane. A sun position calculation showed that the setting sun may have limited the ability of the pilots to see one another.