History of Flight
On June 7, 2020, about 0830 mountain daylight time, an experimental, amateur-built Kitfox 1 airplane, N595KF, was destroyed when it was involved in an accident near Lander, Wyoming. The pilot was seriously injured, and the passenger was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
According to the pilot, he had transported the airplane by trailer from his home in Washington State to Wyoming to see friends and landmarks. The night before the accident, he checked the weather conditions and determined that high winds and turbulent conditions were forecast for around noon the following day. On the morning of the accident, he moved the airplane to Hunt Field (LND) in Lander with a friend and unloaded it from its trailer at 0700. After verifying no significant changes in the forecasted weather, he performed a preflight inspection, gave his passenger a safety briefing, and then departed uneventfully from LND, which is at a field elevation of 5,588 ft mean sea level, about 0730.
The pilot reported that he flew near a cell phone tower about 14 nm south of LND and then turned northwest towards Frye Lake, about 10 nm from the tower at an elevation of about 8,500 ft msl. He stated that the airplane had been in a constant climb for most of the flight due to the high altitude. When they arrived at the lake, he flew northeast of the water and then decided to descend to 500 ft above ground level and fly over the lake before returning to LND. He circled the area momentarily while descending. As they flew over the lake, they encountered turbulence and “sinking air,” which was followed by a sudden descent to a lower altitude. The pilot could not recall the precise altitude but remembered being about eye level with treetops. As the airplane approached the west side of the lake, the pilot advanced the throttle to full power to gain airspeed but was unable to transition into a climb. At this point, he initiated a left turn to avoid impacting a group of recreational vehicles ahead and rising terrain to his right. Subsequently, the airplane entered a nose-down attitude and impacted the water.
According to multiple witnesses, the airplane came into view over the lake on a southwest heading. Witness observations indicated the airplane was about 25 ft agl when it began to “wobble.” It then entered a climb, immediately followed by a steep left turn, and then a nose-down dive. The airplane impacted the water in a near-vertical nose-down attitude, and a fire ensued shortly after impact. Witnesses also stated the airplane appeared to be affected by windy conditions present at the time.
The pilot reported that he normally flies near his home in Port Angeles, Washington (291 ft msl) and seldom flies in mountain environments. The day of the accident was the second time he had departed from a mountain environment. He had received some mountain flying instruction from a Certified Flight Instructor about one year prior and had read a book on the subject.
The airplane did not have a flight manual or performance charts. According to the pilot, the airplane had a normal climb rate of 700 fpm at sea level with a passenger, but he was only able to achieve a climb rate of about 300 fpm after departing Lander. Additionally, he had to make circles as he climbed before reaching a safe altitude before reaching the mountain range.
Meteorological Information
A weather study captured wind information from various sources. A Remote Automated Weather Station (RAWS) located 3 nm from the accident site at 5,589 ft agl, about 3,000 ft lower than the accident site elevation, indicated wind shifted from south at 5 kts to northwest about 9 kts, with gusts to about 11 kts at the time of the accident. Another site in South Pass City, Wyoming, 15 nm away but approximately the same field elevation as the accident site, indicated winds from west at 11 kts gusting to 19 kts with a density altitude of 9,526 ft. The density altitude for the RAWS station could not be determined.
A High-Resolution Rapid Refresh (HRRR) numerical model was completed. The HRRR 0800 wind profile indicated surface wind from the northwest at 6 kts with gusts to 18 kts. Density altitude was computed as 9,461 ft based on surface temperature, dewpoint, and relative humidity estimated by the model. The model further estimated that at 1,000 ft agl over the accident site, wind was from northwest at 25 kts. According to the weather study, the HRRR wind profile and topography would result in rising air or updrafts on the southern side of the ridge 0.5 nm south of Frye Lake and downward flow or downdrafts over the lake. Further, cooler lake temperatures would result in descending air over the lake.
Four of five witnesses observed that the airplane appeared affected by wind conditions. One witness described it as “windy” just prior to the accident, and another referenced updrafts.
According to an Area Forecast Discussion issued at 0415 MDT on the accident day, “Scattered to numerous showers and thunderstorms are expected this afternoon. Although brief MVFR/IFR conditions are possible in convection, VFR conditions are expected to prevail much of the time.” The Terminal Aerodrome Forecast for LND from 0600 through 1000 forecasted variable wind at 5 kts, visibility at least 6 statute miles with few clouds at 7,000 ft agl, and thunderstorms in the vicinity after 1000.
The pilot stated he normally used windy.com and WingX on his electronic tablet for weather planning. The day before, he reviewed forecasts to determine if conditions would be more appropriate Sunday (the accident day) or Monday. His tablet broke in the accident, so he could not recall specific research, but stated he likely reviewed “prognostic charts, wind forecasts, METARs, TAFs, NOTAMs, PIREPs, and SIGMETs.” His research did not reveal any significant weather forecasted for the flight. He reviewed wind conditions for Pinedale, Wyoming and LND and found they would become excessive by 1000 Sunday and Monday was forecasted too turbulent. He normally prefers surface wind below 10 kts. He re-reviewed conditions at 0730 just before the accident, which indicated no significant changes from the night before.
Wreckage and Impact Information
The airplane impacted Frye Lake and came to rest in a near vertical position about 200 ft from the shoreline at an elevation of about 8,517 ft msl. Photographs showed that cowling, cabin, and most of the fuselage were submerged while the aft fuselage and empennage were above water. The left wing was partially submerged, and the right wing was completely submerged. Most of the airplane was consumed by postcrash fire.
During a postaccident examination, flight control continuity was verified to all control surfaces, and no anomalies were identified with the engine that would have precluded normal power production.
Additional Information
The Federal Aviation Administration publication "Tips on Mountain Flying" (FAA-P-8740-60) notes that strong winds can cause dangerous conditions in mountains, and mountain flying should not be attempted if winds aloft at mountain top levels exceed 25 knots. It also states that increasing temperature reduces air density, affecting airplane performance; a normally aspirated engine loses 3% of power per thousand feet of density altitude increase, and wings and propeller become less efficient. Higher density altitudes affect best rate and angle of climb airspeeds.
According to FAA's "Mountain Flying" (AFS-850 17_04), true airspeed is approximately 2% higher than indicated airspeed for every thousand feet of altitude.
The publication also describes accelerated stalls, which can occur at higher-than-normal airspeeds or lower-than-anticipated pitch attitudes and may surprise an inexperienced pilot.