History of Flight
On September 16, 2012, at approximately 0820 mountain daylight time, an experimental light sport KR2S airplane, registration N966G, was substantially damaged when it impacted terrain while maneuvering to land at Pueblo Memorial Airport (PUB), Pueblo, Colorado. The sport pilot, the sole occupant, sustained fatal injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, conducted under 14 CFR Part 91. The flight originated from PUB at about 0814 and was returning to land when the accident occurred.
The airplane departed runway 26L at 0814. Two minutes later, the pilot contacted PUB tower and requested to return due to suspected carburetor icing. The controller cleared the pilot for a left base to runway 26L and offered assistance, which the pilot declined. The pilot was then cleared to land on runway 26L.
The controller observed the airplane approaching the airport fast and appearing to attempt a go-around. The airplane then made a hard right turn, as if aiming for runway 8L. The controller estimated the airplane at about 200 feet AGL in the right turn. It appeared to stall and descended nose-low, right-wing-down, impacting a grassy area near the northwest corner of the intersection of runways 26R and 17.
Personnel Information
The pilot held three FAA certificates: Private Pilot Single Engine Land, Sport Pilot, and Repairman Experimental Aircraft Builder. According to FAA records, the pilot's most recent medical exam was on December 7, 2001, when a Class III medical certificate was issued with a requirement for glasses for near/intermediate vision. The pilot reported 1,500 flight hours at that exam. Pilot logbooks were unavailable, but associates estimated the pilot had about 2,000 total hours, with 200 in the accident airplane.
Aircraft Information
The KR2S experimental homebuilt was constructed by the pilot and issued an Experimental Homebuilt airworthiness certificate on May 5, 2007. It was originally powered by a Lycoming O-235-C2 engine, but an associate reported that this engine had recently been replaced by a Lycoming O-320-A2B. The accident flight may have been the first or second with the new engine. Airframe and engine logbooks were unavailable; total time at the accident was estimated at 200 hours.
Meteorological Information
Reported weather at Pueblo Airport at the time included clear skies, 10 miles visibility, wind from 260 degrees at 7 knots, temperature 12°C, and dew point 4°C.
Wreckage and Impact Information
The NTSB did not travel to the accident site on the date of the accident. The wreckage was moved to a secured hangar and examined on September 20, 2012. All structural and flight control components were identified with no evidence of pre-impact failures. Control cable continuity was confirmed from the cockpit to all surfaces; breaks showed overload features consistent with impact. The engine remained attached to the firewall, and the wooden propeller hub was attached; both blades were fractured and splintered outboard of the hub, consistent with the engine operating at impact.
The engine was separated and secured for examination. The oil sump and carburetor float bowl separated due to impact, and the rear accessory case was fractured. Valve covers and upper spark plugs were removed; spark plugs showed normal wear with slight carbon deposits. A Light Speed Engineering ignition system was installed. Cylinders were inspected with a bore scope; no anomalies were found. The crankshaft was rotated by hand, establishing thumb compression on all cylinders and drive train continuity. No pre-impact engine anomalies were discovered.
Medical and Pathological Information
An autopsy on September 17, 2012, determined the cause of death as multiple blunt force injuries. The FAA's Civil Aerospace Medical Institute performed toxicological tests, which were negative for carbon monoxide and cyanide. Positive results included cetirizine in blood, liver, and urine; citalopram in blood, liver, and urine; diphenhydramine in blood and urine; ibuprofen in urine; metoprolol in blood and liver; N-desmethylcitalopram in blood and liver; and tamsulosin in blood and liver.
Tests and Research
The pilot reported suspected carburetor icing. Review of the carburetor icing probability chart for the reported conditions (temperature 12°C, dew point 4°C) indicated the airplane was in the range of serious carburetor icing at any power setting. The airplane had a carburetor heating system, but impact damage prevented determination of its operational status at the time of the accident.