What happened
The pilot reported conducting an instrument landing system (ILS) approach into Idaho Falls. During the final segment of the approach, he stated that he broke out at approximately 500 feet above ground level (AGL). Upon reaching this altitude, the pilot acknowledged that he did not properly arrest the aircraft's sink rate. Consequently, the aircraft struck the runway surface.
The pilot noted that there was likely ice accumulation under the wings. This ice may have formed during the climb-out phase or as a result of a missed approach executed during a previous attempt at the airport. The ambient temperature at Idaho Falls at the time of the incident was reported to be 33 degrees Fahrenheit.
The investigation
The investigation focused on the pilot's account of the approach and the environmental conditions present during the event. Key factors included the failure to arrest the sink rate at decision altitude and the potential presence of ice contamination on the wing surfaces due to prior flight operations in cold weather.
Findings
Contributing factors to this incident included the pilot's inability to properly control the descent rate after breaking out below decision altitude. Additionally, the probable accumulation of ice under the wings during previous climb-out or missed approach segments likely degraded aircraft performance and handling characteristics. The freezing temperature conditions played a significant role in the potential ice formation.