NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The Diamond flight instructor and student pilot were in the traffic pattern at the non-towered airport practicing landings. The Beech pilot entered the traffic pattern on an extended left downwind leg with the intention of landing. Pilots of other airplanes in the pattern reported that the Diamond instructor was making standard traffic pattern callouts on the common traffic advisory frequency (CTAF); however, the Beech pilot was not transmitting on the CTAF. Witness observations, radar data, GPS data, and examination of the wreckage of the two airplanes revealed that, while both airplanes were on final approach for landing, the Beech overtook the Diamond from above and behind. The landing gear of the Beech struck the horizontal stabilizer and elevator of the Diamond, and then both airplanes abruptly descended into the terrain short of the runway. The Beech came to rest inverted and on top of the Diamond. An examination of wreckage of both airplanes did not reveal evidence of any preaccident anomalies or malfunctions.
Testing of the Beech's VHF communications radio revealed that it was set to an old CTAF frequency for the airport that had been changed about 5 years before the accident. A local airport frequency card dated 7 years before the accident that was found in the Beech's cockpit listed the old CTAF frequency that was set in the Beech's radio. Another pilot at a different airport heard the Beech pilot making pattern calls on the incorrect frequency about the time of the accident.