History of Flight
On September 2, 2014, at approximately 1230 mountain daylight time, a Cessna 177B, registration N34880, struck terrain about 5 miles southeast of Neihart, Montana. The private pilot and one passenger sustained minor injuries, one passenger was seriously injured, and one passenger was fatally injured. The airplane was destroyed by impact and subsequent fire.
The flight departed Great Falls International Airport (GTF), Great Falls, Montana, around 1200 as a personal flight under 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed.
According to the pilot, he checked weather, performed a weight-and-balance calculation, and conducted a preflight inspection. The takeoff and initial climb were normal. About 30 miles southeast of GTF, he descended to allow passengers to photograph a canyon and an old train route. He then executed a climbing 360-degree turn to 7,500 feet and flew along the western ridge, pointing out landmarks. As the canyon narrowed and terrain rose, he initiated a climb. The airplane encountered a downdraft, then a second downdraft. Feeling too low, the pilot attempted to turn around but could not due to narrow canyon walls. He found a low spot in the trees and tried to turn. Despite the nose being up, the airplane would not climb. It brushed trees and descended into them. The final tree impact abruptly turned the airplane before it hit the ground. Fire erupted almost immediately.
The pilot reported no anomalies with the airframe or engine before the accident.
Personnel
The pilot, aged 55, held a private pilot certificate for airplane single-engine land, issued October 25, 2013, and a third-class medical certificate issued February 6, 2013, with the limitation that he must wear glasses for near vision. He had 118 total flight hours, 35 of which were in the accident aircraft make and model.
Aircraft Information
The four-seat, high-wing, fixed-gear Cessna 177B (serial number 17702061) was manufactured in 1974. It was powered by a Lycoming IO-360 series 180-horsepower engine with a McCauley controllable-pitch propeller. The most recent annual inspection was on July 10, 2014. At the accident time, the calculated weight was about 2,614 pounds, exceeding the maximum gross weight of 2,500 pounds. The center of gravity was forward of the envelope throughout the flight.
Meteorological Conditions
The nearest weather station, GTF about 45 miles northwest, reported at 1253: wind from 250° at 13 knots gusting to 19 knots, visibility 10 statute miles, clear skies, temperature 19°C, dewpoint 3°C, altimeter 29.82 inHg. A non-official station 2 miles southwest of the accident site at 8,232 feet recorded gusty winds, including a 22 mph gust just after the accident time.
National Weather Service charts indicated a developing stationary front east of the site and a cold front west, with gusty conditions. An upper-air trough over the site enhanced vertical mixing and turbulence. A North American Mesoscale model sounding showed an absolutely unstable layer from the surface to 10,000 feet, with winds up to 30 knots and expected updrafts and downdrafts in mountainous terrain. A Weather Research and Forecasting Model simulation indicated the airplane likely encountered turbulence and downdrafts with a tailwind component of 100–200 feet per minute, and would not have encountered an updraft until rising terrain south and east of the accident site.
Wreckage and Impact
The airplane came to rest near the top of a ridge in a heavily wooded mountain pass. The 82-yard wreckage path ran downhill, with many downed trees and fragments. The first impact point was a topped tree about 30 feet tall. Approximately 30 yards beyond lay the right stabilator and a red beacon lens fragment. Further along were stabilator end cap fragments, branches, a wheel pant portion, and a 3-foot outboard right wing section with the wingtip, strobe, and green navigation light attached. The left stabilator was nearby. Subsequently, fully downed trees (3–4 inches in diameter) showed smooth diagonal cuts. The main wreckage, inverted and heavily burned, comprised the vertical stabilizer, rudder, left wing, inboard right wing, cabin area, and engine compartment.
Examination revealed no preimpact airframe or engine anomalies. The cabin sustained heavy thermal damage; propeller, throttle, and mixture controls were full forward and heat-damaged. The instrument panel, avionics, and fuel selector were unidentifiable. Control continuity was established throughout the primary flight controls. The fuel system was mostly consumed by fire, but the left wing tank contained several gallons of 100LL fuel. The engine remained intact with extensive thermal damage and could not be rotated; no evidence of catastrophic failure was found. Both propeller blades were bent aft.