What happened
The flight was conducting an approach when it deviated significantly from the planned profile. Data from the National Transportation Safety Board's (NTSB) database indicated that the aircraft did not attain the assigned altitude of 8,200 feet before reaching the outer marker. Additionally, the aircraft failed to establish itself on the localizer course for Runway 34R.
After passing the outer marker, the rate of descent increased sharply. The aircraft impacted hilly terrain at a high rate of speed approximately one mile north of the marker. At the time of impact, the landing gear and flaps were in the up position.
The investigation
A post-crash examination of the aircraft revealed discrepancies in the navigation radio settings. The number one navigation radio was tuned to 117.0 MHz, which corresponds to the Denver VOR frequency. The standby navigation frequency was set to 111.3 MHz, which is the localizer frequency for Runway 34R.
The inbound heading for Runway 34R is 347 degrees. Prior to the accident, the pilot had installed new avionics and an autopilot system in the aircraft. The investigation focused on whether these systems contributed to the navigation errors observed during the approach.