Aviation Accident Summaries

Aviation Accident Summary FTW98LA295

WATKINS, CO, USA

Aircraft #1

N7780U

Cessna 172E

Analysis

The pilot landed at Front Range Airport, Watkins, Colorado, refueled, and waited 90 minutes for a thunderstorm to pass. He then took off en route to Englewood, Colorado. He returned to the airport shortly thereafter because he encountered 'steady state precipitation.' He waited for 30 minutes 'until the rain and virga passed and the wind [had] died down.' He took off from runway 17 into a 4 to 6 knot wind from 160 degrees. After climbing about 400 to 500 feet agl, he began to feel the airplane sinking rapidly. He maintained an airspeed of 60 to 65 knots during the descent, and the stall warning horn sounded intermittently. The airplane collided with rising terrain south of the airport. It was the pilot's opinion that he had encountered a microburst. At the time of the accident, Denver International Airport, located 10 miles northwest of Front Range Airport, reported there were several cumulonimbus clouds at 5500 feet in the area, with winds from the east at 20 knots, gusts to 26 knots, and peak winds at 30 knots. A line of cumulonimbus clouds, stretching from the northwest to the northeast, were moving north with rain showers to the northeast.

Factual Information

On July 2, 1998, approximately 1940 mountain daylight time, a Cessna 172E (tail wheel conversion), N7780U, owned and operated by the pilot, was destroyed when it impacted terrain during takeoff at Watkins, Colorado. The commercial pilot and his private pilot-rated passenger sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight being conducted under Title 14 CFR Part 91. The flight was originating when the accident occurred. According to the pilot's accident report, he had flown from Wray, Colorado, to Front Range Airport, Watkins, Colorado, where he landed, refueled, and waited 90 minutes for a thunderstorm to pass. He then took off en route to Englewood, Colorado. He returned to the airport shortly thereafter because he encountered "steady state precipitation." He waited for 30 minutes "until the rain and virga passed and the wind [had] died down." He took off from runway 17 into a 4 to 6 knot wind from 160 degrees. After climbing about 400 to 500 feet agl, he began to feel the airplane sinking rapidly. He maintained an airspeed of 60 to 65 knots during the descent, and the stall warning horn sounded intermittently. The airplane collided with rising terrain south of the airport. It was the pilot's opinion that he had encountered a microburst. At the time of the accident, Denver International Airport, located 10 miles northwest of Front Range Airport, reported there were several cumulonimbus clouds at 5500 feet in the area, with winds from the east at 20 knots, gusts to 26 knots, and peak winds at 30 knots. A line of cumulonimbus clouds, stretching from the northwest to the northeast, were moving north with rain showers to the northeast.

Probable Cause and Findings

The pilot's inadequate evaluation of the weather which resulted in an encounter with a microburst. Contributing was the airplane's climb capability exceeded by the microburst, and rising terrain.

 

Source: NTSB Aviation Accident Database

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