CEN15LA403

The private pilot reported that, during a preflight briefing, he and the pilot-rated passenger (who was the owner of the airplane) agreed that in the case of an emergency, the owner would take control of the airplane. After takeoff, the sightseeing flight was normal until the airplane approached a glacier at 12,000 ft mean sea level. The pilot stated that because the airplane engine was normally aspirated, there was not much power left to climb, but everything was "ok." As the airplane entered the glacier area through a canyon, it encountered a sudden downdraft and started to descend; the pilot recalled that the airplane's altitude above terrain was about 500 ft. The pilot tried to maintain a level attitude, but the airspeed began to decrease as the airplane continued to descend. The pilot-rated passenger then took control of the airplane and immediately lowered the nose to increase airspeed and set up for an emergency landing; the airplane appeared to be stalling. The airplane landed hard on ice ditches, separating the nose gear. The main landing gear dug in and the airplane came to a stop, which resulted in structural damage to the fuselage. No mechanical malfunctions or failures were reported by the pilot. Because the engine was normally aspirated, the performance of the engine was reduced at a high altitude. Further, the airplane was about 500 ft above terrain when the downdraft occurred. Considering that downdrafts in high mountainous terrain can exceed 1,000 ft per minute, the pilot did not maintain adequate altitude for the operating environment.

On August 16, 2015 about 0930 mountain daylight time, a Cessna 182, XBYUH (Mexican Registry), impacted high mountainous terrain during a forced landing about 37 miles out from the Big Piney, Wyoming VOR (BPI) 015 Degree Radial. Both occupants, the pilot and pilot-rated passenger, sustained minor injuries. The flight was being conducted under the provisions of Federal Code of Regulations Part 91. Visual meteorological conditions prevailed throughout the vicinity and a flight plan was not filed. The local flight originated from the Alpine Municipal Airport (46U) about 0800. The pilot reported that the purpose of the flight was sightseeing. During a preflight briefing, the pilot-rated passenger (who was the owner of the airplane), and the pilot agreed that in the case of an emergency, the owner would take control of the airplane. After takeoff from 46U, the flight was normal until approaching a glacier at 12,000 feet MSL. The pilot stated that because the airplane engine was normally aspirated, there was not much power left to climb, but everything was "OK." As the airplane entered the glacier through a canyon, a sudden downdraft caught the airplane and the airplane started to descend. The pilot recalls that the altitude above terrain was about 500 feet. The pilot tried to maintain a level attitude and the airspeed began to decrease as the airplane continued to descend. The owner then took control of the airplane. He immediately lowered the nose to increase airspeed. Since the airplane was still descending, he asked for flaps and announced that he would execute an emergency landing. The airplane appeared to be stalling. The airplane landed hard on ice ditches, ripping off the nose gear. The main landing gear dug-in and the airplane came to a stop. Figure 1. Approximate flight path into the glacier forced landing area. An American Airlines commercial flight picked up a mayday call and relayed the information to Salt Lake City Air Traffic Control. The wreckage was located by mountain rescue personnel and the two occupants were transported to a local hospital. No mechanical anomalies were reported by the pilot or owner. According to the FAA, downdrafts in high mountainous terrain can exceed 1,000 feet per minute and a normally aspirated engine's horsepower and performance is reduced at high altitudes.