Aviation Accident Summaries

Aviation Accident Summary CHI05LA050

Ainsworth, NE, USA

Aircraft #1

N35403

CESSNA 551

Analysis

The twin-engine corporate jet impacted terrain while maneuvering to land after a global positioning system (GPS) approach. The pilot reported that the airplane entered icing conditions during the approach and that the airplane descended out of instrument meteorological conditions between 300-400 feet above ground level (agl). The pilot reported that his windshield had become obscured by ice accumulation during the approach and that he "had difficulty seeing the runway." The pilot elected to land the airplane instead of executing the published missed-approach procedure. The airplane impacted terrain 439 feet short of the runway threshold while in a right turn. After the accident, there was ice accumulation on all booted airframe surfaces measuring 2-4 inches wide and 1/4 to 3/8 inch thick. The upper portions of the windscreens were contaminated with ice measuring about 3/8 inch thick. The remaining airframe portions, including the heated surfaces, were free of ice accumulation. The windshield bleed air switch was selected on "High" with the pilot's side windshield heat control knob approximately mid-range. Windshield alcohol was selected "On", but the alcohol reservoir was still full upon inspection. At the time of the accident, there was an overcast ceiling of 500 feet agl, 1-3/4 statute mile visibility with mist, and an outside temperature of -08 degrees Celsius. The published minimum descent altitude (MDA) for the GPS runway 17 approach is 500 feet agl, for an airplane equipped with a lateral navigation only GPS receiver. The pilot held a private pilot certificate with multi-engine land, instrument airplane, and Cessna 500 type rating. The pilot reported having 2,200 hours total flight time and 475 hours in the same make/model as the accident airplane.

Factual Information

On January 1, 2005, around 1120 central standard time, a Cessna 551 (Citation II), N35403, piloted by an instrument rated private pilot, was substantially damaged during an in-flight collision with terrain while attempting to land at Ainsworth Municipal Airport (ANW), Ainsworth, Nebraska. Instrument meteorological conditions (IMC) prevailed at the time of the accident. The personal flight was being operated under the provisions of 14 Code of Federal Regulations (CFR) Part 91 while on an instrument flight rules (IFR) flight plan. The pilot and three passengers were not injured. Two passengers reported minor injuries. The cross-country flight departed Reading Regional Airport (RDG), Reading, Pennsylvania, at 0808 eastern standard time. At 1113:16 (hhmm:ss), the accident airplane was cleared for the Global Positioning System (GPS) Runway 17 instrument approach into ANW. The pilot stated that the airplane started to accumulate ice around 4,000 feet mean sea level (msl) during the approach. The pilot reported that he had "all of the anti-ice and deicing equipment working" during the approach. The pilot stated that "at some point the icing conditions became more than the equipment could handle" and the windscreen became obscured by ice. The pilot reported that he descended out of IMC "between 300 and 400 feet" above ground level (agl). The pilot stated that he "had difficulty seeing the runway" due to the accumulation of ice on the windscreen and he elected to land the airplane instead of executing the published missed-approach procedure. A witness to the accident reported seeing the "aft end of a jet heading to the north in a slight bank to the right, I didn't notice the wheels down so I assumed that the jet was making a go-around for another attempt at the approach." The witness stated he didn't see the airplane impact the terrain but did "hear three loud audible pops and saw [what] appeared to be smoke rising over the hangar." On January 2, 2005, a Federal Aviation Administration (FAA) inspector and an airframe representative performed an on-scene investigation. The first point of impact was about 439 feet north of the approach end of runway 17 (6,824 feet by 110 feet, asphalt). The aircraft traveled south about 18 feet prior to contacting an airport access road. The aircraft then became airborne and touched down for the second time after traveling south about 54 feet. The aircraft then slid in a right arc about 700 feet and came to rest parallel to a taxiway that services runway 17. Temperatures at the accident site had remained well below freezing from the time of impact until the on-scene investigation. Pieces of rime ice were found along the wreckage path. These ice pieces were 1/4 to 3/8-inch thick and were shaped similar to the leading edge of a wing. First responders had sprayed the airplane with fire suppression foam after the accident as a precaution. There was no evidence of an in-flight or post-impact fire. The foam had degraded the condition of the ice in some areas along both wings. However, photographs taken by first responders show ice accumulation on all booted surfaces measuring 2-4 inches wide and 1/4 to 3/8 inch thick. The upper portions of the windscreens were contaminated with ice measuring about 3/8 inch thick. The remaining airframe portions, including the heated surfaces, were free of ice accumulation. The windshield bleed air switch was selected on "High" with the pilot's side windshield heat control knob approximately mid-range. Windshield alcohol was selected "On", but the alcohol reservoir was still full upon inspection. The closest weather reporting station to the accident site was located at ANW. The airport is equipped with an Automated Surface Observing System (ASOS). The following weather conditions were reported prior to and after the time of the accident: At 1110: Wind 020 degrees true at 3 knots, visibility 2-1/2 statute miles (sm) with mist, overcast ceiling at 500 feet agl, temperature -08 degrees Celsius, dew point -09 degrees Celsius, altimeter setting 30.03 inches of mercury. At 1130: Wind 030 degrees true at 3 knots, visibility 1-3/4 sm with mist, overcast ceiling at 500 feet agl, temperature -08 degrees Celsius, dew point -09 degrees Celsius, altimeter setting 30.02 inches of mercury. The published minimum descent altitude (MDA) for the GPS runway 17 approach is 500 feet agl, for an airplane equipped with a lateral navigation only GPS receiver. The pilot held a private pilot certificate with multi-engine land, instrument airplane, and Cessna 500 type ratings. The pilot reported having 2,200 hours total flight time and 475 hours in the same make/model as the accident airplane.

Probable Cause and Findings

The pilot's decision to continue below the minimum descent altitude (MDA) and his failure to fly the published missed-approach procedure. A factor to the accident was the pilot's improper use of windshield heat which resulted in the windshield becoming obscured with ice during the instrument approach in icing conditions.

 

Source: NTSB Aviation Accident Database

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