WPR12FA237

The pilot’s decision to take off in known adverse weather conditions and his subsequent failure to maintain sufficient airspeed while maneuvering in mountainous terrain and an area of low ceilings, snow, and fog, which resulted in a loss of airplane control.

The pilot dropped off two passengers at an airport where overcast clouds and occasional snow showers were present and then departed for the return flight to the original departure airport. GPS data indicated that during the return flight the airplane crossed mountainous/hilly terrain. When the pilot reached the western edge of the last mountain ridge, he turned and flew in a northerly direction along its steep western slope. The pilot then performed a 180-degree turn, during which the airplane’s groundspeed increased significantly in a short period of time. Just after the pilot rolled out of the turn, the airplane’s groundspeed suddenly decreased below that required to maintain flight, and, almost immediately, the airplane descended into the terrain. A review of weather information indicated that the base of the overcast cloud layer was below the tops of some of the terrain in this area. Snow showers, strong wind, and patches of fog were present beneath the overcast. It is likely that the pilot flew into the adverse weather or was maneuvering around it when the loss of airplane control occurred. Postaccident examination of the airframe and engine revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation.

HISTORY OF FLIGHT On May 24, 2012, about 1722 Pacific daylight time, a Gulfstream American AA-5A, N26837, impacted the terrain about 40 miles northeast of Lakeview, Oregon. The private pilot, who was the sole occupant, was fatally injured, and the airplane, which was owned and operated by the pilot, sustained substantial damage. The 14 Code of Federal Regulations Part 91 personal cross country flight, which departed Lakeview County Airport, Lakeview, Oregon, about 27 minutes prior to the accident, was being operated in an area where instrument meteorological conditions were reported. The pilot's intended destination was a private airstrip near Hubler, Idaho, which would normally have been about a 2 hour flight. No flight plan had been filed. When the pilot did not arrive at his destination he was reported missing, and a search was initiated. On Wednesday, May 30, the airplane's wreckage was found near the 6,500 foot level of the steep western slope of Hart Mountain, in the Hart Mountain National Antelope Refuge. According to search and rescue personnel, about 2 hours prior to the time he landed at Lakeview, the pilot departed the private airstrip near Hubler, with the intention of flying direct to Lakeview, dropping off two passengers, and then returning to Hubler. According to witnesses on the ground at Lakeview County Airport, the pilot landed there, deplaned two passengers, used the restroom, and then departed again. Recorded global positioning system (GPS) data shows that after his departure from Lakeview, he initially followed a ground track on nearly a direct line between Lakeview, Oregon, and Hubler, Idaho. Then, when he reached a point about 30 miles northeast of Lakeview Airport, near the east shoreline of Plush Lake, he made a 90 degree left turn, flew out toward the middle of the lake, and then turned about 75 degrees back to the right. From there he flew along the west side of the face of the steep mountain ridge that defines the west boundary of the Hart Mountain Antelope Refuge. Then, about five minutes after he had passed over Plush Lake, the pilot initiated a turn to the left. At the time that he initiated the turn, he was flying at a groundspeed of about 95 knots. The GPS data shows that the turn continued for about 180 degrees, so that the plane was then heading almost directly back in the direction from which it had come. The data also showed that just after rolling out of the turn, the airplane’s groundspeed increased to about 158 knots, and then over a period of about 10 seconds, rapidly decreased to about 45 knots. Almost immediately thereafter, the airplane made a nearly 90 degree turn to the left, followed almost immediately by nearly a 90 degree turn back to the right. The last recorded GPS data point was recorded about 3 seconds after the last turn to the right, with the last groundspeed recorded being 21 knots. PESONNELL INFORMATION The pilot was a 48 year-old male, who possessed an FAA private pilot certificate, with an airplane single engine land rating. He did not possess an instrument rating. His last FAA airman’s medical, a class 3 with no limitations or waivers, was signed off on March 7, 2012. His last annotated flight review was signed off in his pilot log on May 12, 2010, and although his last flight time total of 467 hours appears in his pilot log in 2010, he reported at the time of his last medical that his total flight time was 600 hours. AIRCRAFT INFORMATION The airplane was a 1978 Gulfstream American AA-5A, serial number AA5A0755, with a Lycoming O-320E2G engine, and a model 1C172BTM-7359 fixed-pitch McCauley Propeller. Its last annual inspection was signed off on 10 July, 2011, at which time the airframe had accumulated 2,535.88 hours total time. As of February 15, 2011, the engine had accumulated 645.95 hours since a major overhaul. At the time of the accident, the airplane had accumulated about 2,556 hours total time. METEOROLOGICAL INFORMATION The May 24, 2012, 1715 recorded aviation weather surface observation (METAR) for Lakeview Airport indicated a wind of 250 degrees at 10 knots, a visibility of 10 miles, few clouds at 5,000 feet, broken clouds at 7,000 feet, overcast clouds at 8,500 feet, a temperature of 05 degrees C, a dew point of 02 degrees C, and an altimeter setting of 29.72 inches of Mercury. The METAR taken one hour later at the same location indicated a wind from 020 degrees at 14 knots, gusting to 22 knots, a visibility of 10 miles, few clouds at 2,200 feet, broken clouds at 3,300 feet, overcast clouds at 5,000 feet, a temperature of 03 degrees C, a dew point of 01 degrees C, and an altimeter setting of 29.71 inches of Mercury. According to a NTSB Staff Meteorologist, there was an unofficial weather station located about 4 miles west of the accident site at an elevation of 5,650 feet. That station indicated that there had been a significant increase in relative humidity, from 61% to 98%, during the hour prior to the accident. This increase, according to the meteorologist, would suggest cloudy conditions in the general area of the accident site near the time of the accident. The site records also show that during the hour prior to the accident the temperature dropped below freezing, and that about two hours prior to the accident, there was a measured peak wind gust of 33 knots. There was also an AIRMET (Airmen’s Meteorological Information) in effect for the area around the accident site for moderate turbulence. In addition, there were several non-aviation National Weather Service products in effect for the area at the time of the accident, including a Winter Weather Advisory that advised winter conditions, to include snow, terrain obstruction, and gusty west winds up to 30 mile per hour. According to a representative of the Lake County Sheriff’s Office, there was a small group of people who were near the area of the accident site about the time that the airplane impacted the terrain. Although they did not see or hear the airplane, they were able to describe the general weather conditions around that time. According to those individuals, the wind was blowing at a speed estimated to be above 20 mph, with periods of stronger gusts up to about 30 mph. They also stated that the top of the mountain ridge was covered in solid clouds, that it was snowing around much of the area, and that there were some areas of light patchy fog below the clouds. About the same time that the accident pilot was flying toward Lakeview from the north, another pilot, who was flying a Mooney 201 en route from Chandler, Arizona, to Hillsboro, Oregon, was approaching Lakeview from the south. As with the accident pilot, the Mooney pilot was flying by visual flight rules, and in his specific case, was basically trying to follow the Victor airways. When interviewed by the NTSB Investigator-In-charge (IIC), he stated that at first the weather had been mostly okay along his route, with only a few scattered rain showers. But as he reached a point about half way between Reno, Nevada, and Lakeview, in the area just northeast of Susanville, California, the ceilings started to lower, and the areas of precipitation increased. When he reached the Lakeview area, the weather became significantly worse. The ceilings near Lakeview Airport were about 6,500 mean sea level (msl), which was about 1,800 feet above ground level (agl), which ultimately was determined to be within 100 feet of the altitude of the accident site. He also reported that the ceilings were occasionally lower, and that about the same time, he also began encountering a mix of rain showers and snow showers. He reported that the snow was moderate at times, and that as he proceeded north of Lakeview, ice started to accumulate on the airplane’s wings. As he proceeded further north, he was in and out of snow and rain showers, which were interspersed with clear areas underneath the overcast ceilings where he could see up to 20