WPR11FA228

The pilot’s decision to continue flight into an area of known adverse weather, which resulted in an accumulation of structural ice that led to a loss of control and in-flight breakup. Also causal was the pilot’s inadequate preflight weather planning.

The pilot’s initial plan was to make the cross-country flight on the day before the flight actually took place. But, since the weather briefing he received forecast clouds, precipitation, and icing conditions along much of the route, the pilot elected not to attempt the flight but instead decided to wait until the next day. Although the weather briefer advised the pilot that the conditions he had described would still be present along the route of flight the next day, including areas of clouds, low ceilings, precipitation, icing conditions, snow, and thunderstorms, the pilot did not call back for an update briefing on the day of the flight, and he did not receive a weather briefing from either of the Direct User Access Terminal Service providers. It is possible that he may have accessed some raw weather data from a National Oceanographic and Atmospheric Administration website before departing for his planned destination. Overlaying the airplane’s radar track on weather radar imagery indicated that, about 30 minutes after departure, the pilot encountered the edge of the forecast weather conditions, entering an area of precipitation where supercooled liquid droplets had been forecast. This most likely resulted in a very rapid accumulation of ice on the airplane’s structure, including its wings and horizontal stabilizer. Soon thereafter, the airplane entered a steep uncontrolled descent, during which the outboard section of the right wing separated as it was stressed beyond the design limitations of the airplane. The airplane continued in a near vertical uncontrolled descent and impacted the terrain with a high amount of energy. Postaccident examination of the airframe, flight controls, and the engine did not find any evidence of a preexisting anomaly.

HISTORY OF FLIGHT On May 18, 2011, about 1115 mountain daylight time, a Bellanca 17-30A Viking, N93577, impacted the terrain about 40 miles northeast of Rock Springs, Wyoming. The private pilot and his passenger were killed in the accident, 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 Pinedale, Wyoming, about 37 minutes prior to the accident, was en route to Fort Collins, Colorado. At the time of the accident, the pilot was flying through an area of multiple layered overcast and broken cloud formations and light rain. No flight plan had been filed, and there was no report of an Emergency Locator Transmitter activation. On May 17, the day prior to the accident, at 1217, the pilot contacted the Lockheed Martin Flight Service Station, and advised the briefer that he was at Pinedale, Wyoming, and that he was looking to fly via visual flight rules (VFR) to Fort Collins, Colorado. The pilot told the briefer that he was looking at departing sometime in the following four hours, and then stated that he (the pilot) did not think it was looking "particularly good." The pilot then referred to some raw data weather information that he was looking at while he was on the call, and commented that it appeared to him that there was marginal VFR weather around Lander, Wyoming, and that Rock Springs appeared to be having instrument flight rules (IFR) conditions. The briefer then asked the pilot if he wanted a standard briefing, or just an abbreviated briefing, to which the pilot responded that he would take an abbreviated briefing. The pilot then further commented that to him it looked like the route had mountain obscuration and VFR not recommended type of weather along the way. The briefer then informed the pilot that Airmen's Meteorological Information (AIRMET) Sierra for instrument flight rules (IFR) was in effect for his proposed route. He also advised him that AIRMET Zulu, for moderate icing from the freezing level up to 22,000 feet, and AIRMET Tango, for moderate turbulence below 18,000 feet were also valid along his route. He also told the pilot that there was a Convective Significant Meteorological Information (SIGMET) for possible thunderstorms that might affect part of his proposed route. The briefer and the pilot then began discussing the current weather and the forecast for specific locations along the route. Then, about five minutes into the briefing, the pilot asked the briefer what the weather for the next day (May 18) was going to look like. The briefer then told the pilot that the "bad news" was that the trough that was causing the weather activity along the route on the day of the briefing was forecast to stay in the area for another 24 to 36 hours. He then explained that the prognostic charts indicated that the next morning there would be low pressure all along the route, with showers in the morning along the northern part of the route, and snow near the foothills along the southern part of the route. He then informed the pilot that the trend indicated that later in the afternoon there would be thunderstorms along the whole route from Pinedale to Fort Collins. He also advised him that there was a forecast for snow that night (May 17) in Pinedale, and that the expected ceilings in the morning around both Pinedale and Laramie would be around 4,000 feet with a visibility around 5 miles. The pilot then remarked that he could "live with" a 4,000 foot ceiling, and then “dodge the showers." About 7 minutes into the briefing, the pilot made the statement that he could get out of Pinedale right then, and that it looked like there was about a 3,000 foot ceiling. The briefer responded to that comment by trying to clarify if the pilot wanted him to continue to provide more weather information for that day (May 17), or for the next day. The pilot's response to that query was to tell the briefer to just give him the terminal forecast for the Denver area (for May 17). The briefer gave the pilot part of the terminal area forecast (TAF) for Denver, but was then interrupted by the pilot stating that he had a copy of the TAF in front of him, and that he needed to learn to read it. Then, for about a minute and a half, the pilot asked the briefer questions about what specific numbers, letters, and abbreviations on the TAF meant. The pilot then told the briefer that they would be making their decision (on whether to go then, or the next day), and then thanked the briefer for his help. The briefer then advised the pilot that there were no temporary flight restrictions or adverse NOTAM's (Notice to Airman) along the route, and then commented that there were some showers already starting north of Walden and South of Laramie. The pilot then asked the briefer if he knew what tops of the showers were at that time, and the briefer advised him that they were between 25,000 and 30,000 feet. A few seconds later the pilot advised the briefer that he was looking out the window, and that it was starting to snow in Pinedale at that time. A few seconds after the pilot’s comment about the snow, the pilot terminated the briefing session. The next morning the pilot did not contact Flight Service for an update briefing, nor did he make use of the services of either Direct User Access Terminal Service (DUATS) providers (although, according to his wife, he often used the data provided on the National Oceanic and Atmospheric Administration site). The pilot did not file a flight plan for a flight on the morning of May 18, but according to recorded radar data, he did depart Pinedale about 1038, and climbed out on a track of about 148 degrees, leveling off around 9,300 feet mean sea level (MSL) at a point about 17 miles southeast of the airport. The pilot then turned right about 50 degrees, and proceeded on a track of about 188 degrees for about 12 miles. The radar data shows that he then executed a 2-mile diameter right turn of about 270 degrees duration, and continued on a track of about 118 degrees for about 28 miles. He then turned left about 55 degrees, and continued on a track of about 63 degrees for about another 20 miles. Up to that point in time, the pilot had maintained an altitude within about 300 feet plus or minus of 9,000 feet MSL. About 1110, the pilot turned right to a track of about 128 degrees, and climbed to about 11,000 feet. He continued on that track for about 5 miles, where, according to recorded radar imagery, the airplane encountered the western edge of a series of rain shower bands in an area where icing conditions within precipitation were favorable. About 1114, the airplane entered a descending right turn, during which it descended about 2,800 feet in about 30 seconds (an average rate of about 5,800 feet per minute). The airplane was then lost from radar while passing through 8,000 feet, at a location of 42 degrees, 10 minutes, 41 seconds North by 108 degrees, 47 minutes, 44 seconds West. The airplane impacted the terrain at 42 degrees, 10 minutes, 40.95 seconds North by 108 degrees, 47 minutes, 50.12 seconds West, which was about one-tenth of a mile west of the last radar hit. While en route, the pilot was not in contact with an Air Route Traffic Control Center (ARTCC), and therefore no one knew that the airplane was missing until the pilot did not arrive at his intended destination, and family members became concerned. Based upon the information provided by the family members, an alert notice (ALNOT) for a missing aircraft was issued. PESONNELL INFORMATION The pilot was a 55 year old male who possessed a private pilot certificate with an airplane single engine land rating. He did not hold an instrument rating. His last airman’s medical, a third class, was completed on April 4, 2010. His last flight review was conducted on March 23, 2010. As of the end of December 2010, which was the date