Cheyenne, WY, USA
N26908
GULFSTREAM AMERICAN CORP AA 5
The flight instructor and student pilot were departing on an instructional cross-country flight when, just after takeoff, the airplane encountered wind and turbulence. The instructor had difficulty maintaining altitude and elected to perform an off-airport precautionary landing, during which the right wing sustained substantial damage. A weather study revealed conditions conducive to low-level wind shear and turbulence at the accident site at the time of the accident. Although the instructor had received an abbreviated weather briefing before departure, the briefing did not advise of the potential for low-level wind shear. It is likely that the encounter with wind shear during departure made it difficult for the airplane to maintain altitude.
On July 7, 2016, about 1155 mountain daylight time, a Gulfstream American CORP AA-5A airplane, N26908, was substantially damaged during a forced landing after departing Cheyenne Regional Airport/Jerry Olson Field (KCYS), Cheyenne, Wyoming. The flight instructor and student pilot were not injured. The instructional flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a visual flight rules flight plan had been filed for the flight. The flight was originating at the time of the accident and was en route to Eppley Airfield (KOMA), Omaha, Nebraska. The flight instructor stated that the takeoff was normal; however, at the departure end of the runway, between 300 and 400 feet above the ground, "the wind started blowing from all directions" and he had difficulty maintaining control of the airplane. The flight instructor had difficulty maintaining altitude and elected to land the airplane on the road next to a school. During the landing roll, the flight instructor maneuvered the airplane to avoid hitting construction workers directly ahead of him. The right wing hit a construction sign and was substantially damaged. The pilot stated that there were no mechanical anomalies with the airplane or engine at the time of the accident. A weather study was conducted by a meteorologist with the National Transportation Safety Board. The National Weather Service charts depicted a low pressure system over southeast Wyoming and a mid-level trough just west of the accident site. Winds at the 700-hPa level were westerly around 10 knots, whereas winds at the 500-hPa level increased to 60 knots. There were no AIRMETs, SIGMETs, or center weather advisories valid for the accident site at the time of the accident. One PIREP in the area reported moderate "chop" between 6,500 feet and 8,500 feet mean sea level. The terminal aerodrome forecast valid at the time of the accident forecast winds from 300° at 12 knots gusting to 20 knots. Cheyenne Regional Airport had the closest official weather station to the accident site, 2 miles south-southeast of the accident location. The observation taken at 1153 reported wind 090° at 9 knots, and clear skies. The observation taken at 1208, after the accident, reported wind from 090° at 7 knots. The closest non-official surface observation site (5 miles west of the accident site) reported wind from 274° with gusts to 19 knots at 1215. Weather service radar depicted a dry-line boundary at the accident site, at the time of the accident. Wind speed and direction changed with altitude associated with this dry-line boundary and would have had a corresponding increase in low-level turbulence and low-level wind shear. A search of official weather briefing sources revealed that the flight instructor contacted Lockheed Martin Flight Service at 0853 on the morning of the accident and received an abbreviated briefing for the flight from Rock Springs, Wyoming, to Cheyenne, Wyoming. There was no record of the flight instructor receiving or retrieving any additional weather information before the accident flight.
The airplane’s encounter with low-level wind shear during takeoff, which resulted in an off-airport landing.
Source: NTSB Aviation Accident Database
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