Van's RV-4 N456MC

Summary

On 8 December 2021 at about 17:13 local time, a Van's RV-4 registered N456MC was involved in an accident near Walsenburg, Colorado, United States. One person was on board and one died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

8 December 2021 at 17:13

Classification

Accident

Location

Walsenburg, Colorado, United States

Coordinates

37.7928, -104.5762

Aircraft

Van's RV-4

Registration

N456MC

Category

Airplane

Year built

2020

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Colorado Springs → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN22FA064

1 person died.

The pilot’s failure to maintain clearance from terrain while intentionally maneuvering in a canyon at low altitude. Contributing to the accident was the pilot’s decision to enter a canyon environment at a low altitude, and the sudden change in wind conditions within the canyon.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The accident occurred during a three-airplane formation flight to practice position changes and low-level maneuvering. About 30 minutes after takeoff, the pilots began a descent toward a reservoir, with the accident airplane as the lead. The airplanes were in a right-echelon route formation and were prepared to go to a trail formation for low-level maneuvering in the river canyon. About 1 mile north of the reservoir, the accident pilot directed the two other pilots to “go trail,” and he executed a left turn and descent toward a river canyon that extended north of the reservoir. The pilots reported they entered a descent and encountered strong surface winds and turbulence above the canyon rim. The accident pilot’s airplane descended below the canyon rim and continued the descent to near the bottom of the canyon. One pilot reported there was a strong south-southwest wind (210° at 35 mph) a couple thousand feet above the surface, so he remained above the canyon rim to assess potential turbulence. During the third turn and less than a minute inside the canyon, the pilots observed the accident airplane’s left wing contact the edge of the canyon at high speed. The airplane fragmented and came to a stop in the canyon. Postaccident examination of the airplane revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operations. Local authorities who responded to the accident location reported intense and variable winds within the canyon that were different than the winds they encountered above the canyon rim. Available weather information indicated that conditions in the vicinity of the accident site were favorable for the presence of moderate-to-severe turbulence. The circumstances of the accident are consistent with the pilot’s loss of control due to high-speed, variable wind conditions while maneuvering at low altitude in a canyon. The autopsy revealed the pilot’s severe coronary artery disease put him at risk for an acute coronary event, which could acutely cause chest pain, shortness of breath, palpitations, or fainting. However, there is nothing about the operational information in this investigation to suggest such an event contributed to the circumstances of the accident. Therefore, it is unlikely his coronary artery disease contributed to this accident.

Quoted verbatim from the NTSB record.