Van's RV4 N87LW

Summary

On 26 November 2020 at about 19:59 local time, a Van's RV4 registered N87LW was involved in an accident near Telluride, Colorado, United States. 2 people were on board and 2 died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

26 November 2020 at 19:59

Classification

Accident

Location

Telluride, Colorado, United States

Nearest airport

Telluride Regional Airport (TEX)

Coordinates

37.9491, -107.8886

Aircraft

Van's RV4

Registration

N87LW

Category

Airplane

Year built

1987

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Durango → Telluride

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN21LA067

2 people died.

The pilot’s failure to maintain adequate airspeed during the turn from the base leg to final approach, which resulted in the airplane exceeding its critical angle of attack and entering an inadvertent aerodynamic stall/spin at a low altitude over mountainous terrain.

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

Read the full NTSB narrative

The pilot and passenger were concluding a cross-country flight and were flying in the traffic pattern at their intended destination when the airplane pitched nose down and descended rapidly into mountainous terrain during the turn from the base leg to final approach. There were multiple witnesses who reported seeing the airplane enter a steep left turn toward the airport followed by a nose-down descent toward terrain. One witness reported that the airplane completed 3 or 4 spins while it descended nose down in a vertical descent and that the sound of the engine was “quite loud.” Airport security camera footage showed the airplane in a left-wing down, nose down, descending turn into terrain east of the airport. According to automatic dependent surveillance-broadcast (ADS-B) data, shortly after the airplane entered the left turn from the base leg to final approach, the airplane decelerated to 50 knots calibrated airspeed (KCAS) and the descent rate increased from 600 to 3,850 ft/min. According to the airplane kit manufacturer, the airplane’s wings-level aerodynamic stall speed at a maximum gross weight was 47 KCAS. The airplane maneuvering in the traffic pattern would require turns and, as such, there was a corresponding increase to aerodynamic stall speed during the turns. Additionally, the airplane’s left-wing-down roll was increasing when the airplane entered the rapid descent. Postaccident examination revealed no evidence of a preexisting mechanical malfunction or failure that would have precluded normal operation of the airplane. Based on the surveillance video footage, witness accounts, and the recorded ADS-B data, it is likely the pilot did not maintain adequate airspeed during the left turn from the base leg to final approach, which resulted in the airplane exceeding its critical angle of attack and inadvertently entering an aerodynamic stall/spin at a low altitude over mountainous terrain. Toxicology testing detected morphine in the pilot’s urine but not in his blood. The detection of acetaminophen suggests that the pilot had taken codeine with acetaminophen for mild to moderate pain relief. Since no morphine was present in the blood, no impairing effects would be expected. Thus, the effect of the pilot’s use of morphine or opiate pain reliever was not a factor in this accident.

Quoted verbatim from the NTSB record.