Cessna 172 N5660J

Summary

On 13 August 2018 at about 15:08 local time, a Cessna 172 registered N5660J was involved in an accident near Afton, Wyoming, United States. 3 people were on board and 3 were seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

13 August 2018 at 15:08

Classification

Accident

Location

Afton, Wyoming, United States

Coordinates

42.7202, -110.9326

Aircraft

Cessna 172

Registration

N5660J

Category

Airplane

Year built

1980

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Afton → Afton

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR18LA241

3 people were seriously injured.

The pilot’s failure to maintain terrain clearance after an encounter with a downdraft while maneuvering in a valley with a high-density altitude, which resulted in impact with trees and terrain.

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

Read the full NTSB narrative

An airline transport pilot and two passengers departed on an aerial observation flight in mountainous terrain. While flying in a valley, the pilot reported that he experienced downdrafts, which made it unlikely that the airplane would clear the ridge lines in front of the airplane. The pilot performed a steep 180° left turn to exit from the high terrain. However, after completing the turn, the airplane was unable to climb over terrain and struck several trees before impacting the ground, which resulted in substantial damage to the wings and fuselage. The pilot reported no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The airplane's weight and balance was calculated as about 256 pounds below the maximum gross weight limit, and the density altitude at the accident was calculated as about 8,765 ft mean sea level (msl). A weather study of the accident area identified no significant winds, turbulence, or low-level wind shear present or forecast. The study did identify a surface-based inversion that existed to about 500 ft above ground level (agl). Additionally, another pilot in a different airplane stated that moderate turbulence was present near the accident area about 18 minutes before the accident. Due to a combination of the airplane's high gross weight, a high-density altitude, a temperature inversion, maneuvering at a steep bank in order to avoid high terrain, and with potential downdrafts, the pilot dissipated the airplane's airspeed and altitude, and approached a stall. With no altitude available to increase the airspeed after the left turn and already at full power, the airplane continued to descend until it struck trees and impacted terrain.

Quoted verbatim from the NTSB record.