Carrollton, GA, USA
N849CA
ALLEN STEEN SKYBOLT
The pilot, who was the airplane owner, was on a local, pleasure flight. Witnesses observed the airplane flying low followed by a rapid pitch down or loss of airplane control. The airplane struck a tree about 60 ft above the ground and continued another 46 ft until it struck the ground. Most of the wreckage was consumed in a postaccident fire. Primary flight control continuity was confirmed from the control surfaces to the cockpit controls. All of the airplane's primary structural components were accounted for within the wreckage debris field. Several tree branches with smooth, angular cuts, indicative of contact with a propeller under power, were observed within the wreckage debris field. A disassembly and examination of the engine revealed no evidence of a preexisting mechanical malfunction or failure. A cable attachment bracket for the elevator trim tab was found fractured; however, examination of the fracture surface revealed overstress signatures, and no evidence of a preexisting anomaly was found. Thus, the fracture likely occurred during the impact sequence. The pilot, who had owned the airplane for about 15 years, only flew it occasionally, and his last logged flight in the accident airplane was more than 1 year before the accident flight. The pilot's autopsy and toxicology reports revealed no evidence of incapacitation.
HISTORY OF FLIGHTOn July 13, 2014, about 1725 eastern daylight time, an experimental, amateur-built Allen Steen Skybolt, N849CA, was destroyed following an inflight loss of control and a collision with trees and terrain near Carrollton, Georgia. The commercial pilot and one passenger were fatally injured. The experimental, amateur-built airplane was registered to a corporation and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Day, visual meteorological conditions prevailed and no flight plan was filed. The local flight originated from West Georgia Regional Airport, Carrollton, Georgia, about 1640. Reportedly, the pilot was on a local area pleasure flight with his grandson. Several witnesses observed the airplane in flight and the accident sequence. Most witnesses observed the airplane flying low, followed by a sudden pitch down or loss of airplane control. Three witnesses reported that the engine continued to run normally until impact, while two witnesses reported that the engine was "sputtering" and/or "backfiring." Another witness reported the engine at "low power not idle." PERSONNEL INFORMATIONThe pilot, age 70, held a commercial pilot certificate with ratings for airplane single engine land, airplane multi-engine land, and instrument airplane. He reported a total flight experience of 2,710 hours, including 35 hours during the last six months, on his limited third class medical certificate application, dated May 12, 2014. The medical certificate included a restriction to wear corrective lenses. The pilot's most recent logbook was provided to the investigation team by family members. The first entry was recorded on July 1, 2011, at a total forwarded flight time of 2,485.5 hours. The last logged entry was on June 25, 2014, in a Piper PA-31. His total logged flight time was 2,730.7 hours, including 1,454.1 single engine and 395.0 hours in tail wheel airplanes. The pilot's logged flight time in the accident airplane, since July 1, 2011, was 6.1 hours, encompassing 6 flights. The last logged flight in the accident airplane was on May 21, 2013. AIRCRAFT INFORMATIONThe airplane was Steen Skybolt, built by Charles Allen in 1975. The experimental, amateur-built, bi-wing, tail wheel landing gear airplane was powered by a Lycoming O-360-A1D engine rated at 180 horsepower at 2,700 rpm. It was fitted with a Hartzell HC-C2YK-1A, two-bladed, constant speed propeller. An examination of available maintenance records revealed that a conditional inspection was performed on the airframe and engine on April 8, 2014. The airframe total time at the conditional inspection was 860.75 hours. According to Federal Aviation Administration records, the accident pilot acquired the airplane from the previous owner, who was also the airplane builder, in October, 1999. METEOROLOGICAL INFORMATIONThe 1735 surface weather observation for Carrollton, Georgia (CTJ), located about 9 miles west-northwest of the accident site, included sky clear, wind from 180 degrees at 4 knots, visibility 10 statute miles or greater, temperature 90 degrees F, dew point 68 degrees F, and altimeter setting 30.08 inches of mercury. AIRPORT INFORMATIONThe airplane was Steen Skybolt, built by Charles Allen in 1975. The experimental, amateur-built, bi-wing, tail wheel landing gear airplane was powered by a Lycoming O-360-A1D engine rated at 180 horsepower at 2,700 rpm. It was fitted with a Hartzell HC-C2YK-1A, two-bladed, constant speed propeller. An examination of available maintenance records revealed that a conditional inspection was performed on the airframe and engine on April 8, 2014. The airframe total time at the conditional inspection was 860.75 hours. According to Federal Aviation Administration records, the accident pilot acquired the airplane from the previous owner, who was also the airplane builder, in October, 1999. WRECKAGE AND IMPACT INFORMATIONThe wreckage was located in a heavily wooded area. The airplane initially impacted a white oak tree, about 60 feet above the ground. The upper, right section of the wing remained lodged in the tree. The remainder of the wreckage impacted the ground about 46 feet north-northeast of the impacted tree. The entire wreckage path was about 105 feet in length, oriented on a heading of 030 degrees magnetic. Numerous tree limbs, up to 5 inches in diameter, with smooth, angular cuts were located within the wreckage debris field. A post-crash fire consumed a majority of the main wreckage. All components and fragments of the wreckage that were outside of the ground fire area were free of soot or evidence of fire. All major airframe structural and flight control components were accounted for within the wreckage debris field. Flight control continuity was established from the cockpit control stick to the ailerons. All fractures in the aileron control rods were consistent with overload. Elevator and rudder control continuity was confirmed from the cockpit controls to the control stick and the rudder pedals. One of two welded steel brackets connecting the elevator trim tab to the control cables was broken and showed indications of fire and heat damage. The assembly was forwarded to the NTSB Materials Laboratory in Washington, DC for examination. The propeller assembly broke free at the engine crankshaft, just aft of the propeller flange, and was located about 50 feet north-northeast of the engine. The propeller was the furthest component found along the wreckage path. The fracture to the crankshaft showed signatures consistent with overload. The engine remained attached to the airframe by control cables. Two sets of four-point seat belt buckles were located within the cockpit area. The buckles remained fastened and the webbing was consumed by the post-crash fire. The metal fuel tank was ruptured and burned and was located within the area of the fuselage. The fuel cap was secure. The fuel line from the tank to the engine was consumed by the post-crash fire. The cockpit instruments were burned in the post-crash fire and no useful information was obtained from them. The cockpit-mounted engine controls were found in the retarded (aft) positions. After the wreckage was recovered from the accident site, the engine was examined at a wreckage storage facility in Griffin, Georgia. The engine was exposed to the post-crash fire and was burned or melted in several areas. The spark plugs were removed and examined. The electrode wear and deposits were normal when compared to a Champion inspection chart. The magneto cases were partially melted and the units could not be tested. The leads were partially burned away. The heat and fire-damaged carburetor was removed and disassembled. The composite floats were charred but in place. The bowl was clean and dry and no residual fuel found. The cylinders were removed and engine was disassembled. Other than post-crash fire and heat damage, no anomalies were noted with the cylinders, valves, pushrods, and pistons; power train continuity was established and all components indicated normal operating signatures. The engine case, crankshaft, camshaft and bearings were normal in appearance, except for heat distress from the post-crash fire. The examination of the engine did not reveal any evidence of a pre-existing anomaly or malfunction. MEDICAL AND PATHOLOGICAL INFORMATIONA postmortem examination of the pilot was performed at the offices of Georgia Bureau of Investigation, Division of Forensic Sciences, Decatur, Georgia on July 14, 2014. The autopsy report noted the cause of death as "Multiple blunt impact injuries" and the manner of death was "Accident." Forensic toxicology testing was performed on specimens of the pilot by the Federal Aviation Administration (FAA) Bioaeronautical Sciences Research Laboratory (CAMI), Oklahoma City, Oklahoma. The CAMI toxicology report indicated no carbon monoxide testing was performed due to a lack of suitable specimens. Testing for cyanide was not performed. No ethanol was found in the urine. Amlodipine was detected in the urine, but not in the blood. The pilot reported that he was taking amlodipine on his latest FAA medical certificate application. According to the FAA Aerospace Medical Research Forensic Toxicology website, Amlodipine is a calcium channel blocker heart medication used in the treatment of hypertension. Salicylate (aspirin) was detected in the urine. TESTS AND RESEARCHThe elevator trim tab and connecting hardware were sent to the NTSB Materials Laboratory for examination. The fracture surface was initially examined as-received and was subsequently cleaned with a solution of alconox and water using a soft-bristle brush. A portion of the fracture surface at the aft end of the fracture had mostly intergranular fracture features with some transgranular facets. The remainder of the fracture surface appeared oxidized with no discernible fracture features. Next, the fracture surface was deoxidized by immersion in Evapo-Rust1 for 6 hours. The deoxidized fracture surface was then examined using a scanning electron microscope. The fracture surface outside of the intergranular region was mostly obscured by oxidation that remained on the surface. However, a few isolated areas of fracture features were observed. The fracture features in those areas showed dimple fracture features consistent with ductile overstress fracture.
An in-flight loss of airplane control for reasons that could not be determined during postaccident examinations or based on the available evidence.
Source: NTSB Aviation Accident Database
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