What happened
The aircraft was operating under visual flight rules when it initiated a "pop-up" request for instrument flight rules clearance. Air traffic control subsequently issued an instrument flight rules clearance for an approach into Cheyenne Airport. During the execution of a circling approach, the pilot attempted to transition to final approach. While maneuvering in this phase of flight, the aircraft lost controlled flight and collided with the terrain.
The investigation
Investigators examined the wreckage site to determine the mechanical condition of the aircraft at the time of impact. The examination revealed that there was a significant accumulation of mixed rime and clear ice on the engine. This buildup suggests that the aircraft had been operating in conditions conducive to airframe icing, which likely degraded aerodynamic performance and contributed to the loss of control during the critical maneuver.
Findings
The primary factors leading to the accident included the operational environment and the specific phase of flight. The pilot was conducting a circling approach under instrument flight rules, a maneuver that requires precise spatial awareness and aircraft handling. The presence of ice on the engine indicates exposure to in-flight icing conditions without adequate de-icing or anti-icing measures being effective. The combination of the complex maneuver and environmental factors resulted in the ground collision.
Safety message
Pilots operating in icing conditions must be vigilant regarding airframe ice accumulation, particularly during low-speed maneuvers such as circling approaches. Effective use of de-icing systems and awareness of weather conditions are critical to maintaining aircraft performance and control.