What happened
During a night cargo operation under instrument flight rules (IFR), a twin-engine turboprop was performing a localizer DME back course approach to runway 36. The flight crew had previously noted an altimeter setting of 29.30 inHg from the ATIS. While inbound for the approach, the tower updated the crew regarding weather conditions, noting one mile of visibility in light snow and a wind of 040 degrees at 22 knots, alongside a new altimeter setting of 29.22 inHg. The crew failed to update the aircraft altimeters to reflect this change.
As the aircraft reached the final approach fix, five miles from the runway, the captain initiated a descent toward the minimum descent altitude (MDA) of 460 feet MSL. Shortly before the collision, the first officer noted that the aircraft was maintaining a high airspeed. In response to significant crosswinds, the captain disengaged the autopilot 22 seconds prior to impact. Although the aircraft briefly leveled off at approximately 471 feet indicated altitude, it subsequently began a descent. The aircraft struck the ground 3.5 miles from the runway. The crew did not observe the airport or the snow-covered terrain before the crash, and the landing lights were not in use at the time of impact.
Findings
- The crew did not adjust the aircraft altimeters to the updated barometric pressure of 29.22 inHg.
- The aircraft lacked a ground proximity warning system.
- The impact occurred during a descent following a period of manual flight control necessitated by strong crosswinds.