CIRRUS DESIGN CORP SF50

Full Narrative

On January 3, 2025, about 2338 mountain standard time, a Cirrus Design Corporation SF-50 airplane, N603AP, was substantially damaged when it was involved in an accident near Spearfish, South Dakota. The pilot and five passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot reported the flight proceeded uneventfully until landing. The air traffic controller advised him that the Black Hills Airport-Clyde Ice Field (SPF) runway was covered with 1/8” of wet snow and runway braking action was reported as 5/5/5 (touchdown/midpoint/rollout). The pilot noted the airport was in sight about 4 miles out, and he executed a straight-in approach to runway 13. He verified that the landing gear was down. His intention was to touchdown at the landing reference speed (Vref) to minimize the need for braking. The airplane was lined up with the extended runway centerline and the pilot disconnected the autopilot about 2 miles from the runway.
The pilot recalled receiving an aerodynamic stall warning and stick shaker activation about 8 to 10 ft above ground level (agl) during landing. At first, the touchdown seemed normal, but then the airplane started to drift to the left. The pilot’s efforts to maintain directional control were not successful. The airplane “lurched hard” when it impacted the snowbank along the left side of the runway. When the airplane came to rest, the pilot shut down the engine, and the airplane was evacuated.
One of the passengers reported that he was seated behind the right-side co-pilot seat and had a “good view” out of the windshield. He confirmed seeing the 3-green landing gear down lights while on approach. He noted that the airplane appeared to be aligned with the runway but was slightly left of the centerline. As the airplane touched down, it quickly drifted to the left. The left wing then caught the snowbank, and the airplane departed the left side of the runway. The airplane ultimately came to rest with the nose perpendicular to and facing the runway. The passenger recalled that when he exited the airplane, the wind was almost calm. Another passenger estimated about 2 to 3 inches of snow was covering the runway when they evacuated the airplane.
The onboard recoverable data module (RDM) provided flight and engine parameter data for the accident flight. The data indicated that the airplane crossed the SOPHI final approach fix on the RNAV (GPS) runway 13 approach about 2335:20 at 5,389 ft and 168 knots indicated airspeed (KIAS). The wing flaps were configured at 50% at that time. About 12 seconds later, the autopilot captured the glidepath. The autopilot disconnected at 2336:56 when the airplane was about 1.6 nm from the runway. This was consistent with the pilot’s statement regarding intentionally disconnecting the autopilot during the approach before landing.
According to the RDM data, the airplane crossed the runway arrival threshold at 2337:49. The altitude and airspeed were about 3,904 ft and 92 KIAS, respectively. About 5 seconds later, the airplane touched down about 820 ft past the runway threshold at 85 KIAS. The airplane subsequently departed the left side of the runway and came to rest about 1,400 ft from the threshold. The aerodynamic stall warning parameter was not active at any point during the accident flight. Weight on wheel data was not an available parameter on the RDM.
An examination of the accident site by a Federal Aviation Administration (FAA) inspector the following day revealed runway wheel marks (compressed snow) corresponding to the accident airplane beginning about 150 ft before the touchdown zone (1,000-ft) markers. At touchdown, the left main wheel was 6 to 8 ft from the left side of the runway (about 30 ft left of centerline), and the airplane appeared to depart the left side of the runway about 140 ft after the beginning of the wheel tracks. The snowbanks on each side of the runway were 2 to 3 ft high. The airplane struck two runway edge lights during the runway excursion.
A postaccident examination by the FAA inspectors revealed damage to the outboard right wing including partial separation of the right aileron. The left main landing gear remained extended; however, the right main landing gear was retracted in the wheel well, and the nose landing gear was collapsed. Further examination revealed the right main landing gear actuator was fractured along the length of the housing. The fracture surface exhibited features consistent with an overstress failure. Additionally, the housing was deformed outward at the fracture consistent with an overpressure event. The right main landing gear tire was flat.
The airplane flight manual specified approach reference speeds of 91 KIAS and 96 KIAS with 50% flaps and operating weights of 5,000 lbs. and 5,500 lbs., respectively. Aerodynamic stall speeds with 50% flaps and 0° angle of bank were noted at 72 KIAS and 74 KIAS at operating weights of 5,200 lbs. and 5,550 lbs., respectively.
Data recovered from the onboard Centralized Maintenance Computer (CMC) included multiple engine parameters. Specifically, the engine interstage turbine temperature (ITT), compressor speed, turbine speed, oil temperature, and oil pressure. Each of these parameters remained within the specified limits for the duration of the accident flight. This was consistent with normal engine operation during the flight.