Williamstown, KY, USA
N3EG
Sorrell Aircraft Skybolt
While in cruise flight at 2,000 feet the engine suddenly stopped producing power. The pilot and passenger, wearing parachutes, elected to parachute to the ground. Eyewitnesses reported seeing the pilot leave the airplane approximately 10 to 15 seconds after the passenger departed and after placing the airplane in a nose dive. The airplane impacted a rectangular farm field and the pilot and passenger suffered serious injuries due to the low altitude in which they parachuted from. The airplane had been purchased by the accident pilot approximately one month prior to the accident. According to the airplane's engine maintenance log, on April 28, 2004, the engine had undergone a preservation process called "pickling." The process utilized 10 quarts of pickling oil and the engine was placed in storage. On May 9, 2006 the engine was drained of the pickling oil and replaced with 7 quarts of 50 WT oil. The cylinders were drained and cleaned, and then the engine was test ran. The NTSB Materials laboratory examined components of the engine and analyzed an unknown substance within the lubricating journals of the camshaft and crankshaft. The compounds of the unknown substance was those found in corrosion preservation fluids also known as pickling fluids and are not found in lubricating oil. The presence of these compounds indicates that it was likely that some pickling fluids were still in the engine at the time of the accident; however, a specific pickling fluid could not be determined. According to the engine manufacturer, pickling fluid has been known to clog lubrication channels by forming a tarry residue when present in engines for prolonged periods and result in oil starvation. The number 2 main bearing and piston were thermally damaged and that thermal damage is consistent with oil starvation. Therefore it is possible that the residual pickling fluid clogged the lubrication channels for the number 2 position resulting in oil starvation.
On September 21, 2008, about 1920 eastern daylight time, a Sorrell Skybolt, N3EG, was substantially damaged when it impacted a farm field near Williamstown, Kentucky. The certificated private pilot and his passenger were seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed. The personal local flight departed from Gene Snyder Airport (K62), Falmouth, Kentucky about 1900. The flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. According to the passenger, while in cruise flight, the airplane’s engine had a complete loss of power. The pilot and passenger were each wearing parachutes, and they both exited the airplane while it was still airborne. The pilot reported that while they were in "cruise flight at 2,000 feet the engine failed." He attempted to restart the engine however the engine failed to start. Since he was taught to always fly with a parachute as a safety precaution he ordered his passenger to parachute out of the plane. The passenger left the airplane at approximately 500 feet above ground level and he parachuted shortly afterwards. Witnesses to the accident reported to the Federal Aviation Administration (FAA) inspector on scene that after the first occupant left the airplane, the airplane appeared to be placed in a nosedive, and the second occupant parachuted approximately 10 to 15 seconds later and that the pilot and passenger exited the airplane when it was approximately 200 feet above ground level. The witnesses stated that the first occupant’s parachute appeared to "flutter," and not fully open. The witnesses observed that the second occupant's parachute did not have enough time to fully open and arrest the descent. The witnesses went to locate and provide aid to the two occupants. The pilot was located near the edge of a tree line lying back down over a downed tree. An inspector from the FAA examined the airplane. According to the inspector, the airplane impacted the ground in a nose down attitude. The airplane fragment furthest from the main wreckage was a window segment located approximately 14 feet away. The inspector stated that the lead-acid battery had separated from its attachment, and that a small fire occurred where the battery was found. No other fire damage was observed in the wreckage. A connecting rod protruded through the engine block. No oil was observed on the underside of the fuselage. The fuel tank was ruptured, but there was no odor or other evidence of fuel at/near the accident site. The airplane forward of the rear seat exhibited extensive compression damage. Aileron control continuity was confirmed from each wing root to the associated aileron, and rudder continuity was confirmed from aft of the rear seat to the rudder. Due to the damage to the cockpit area, continuity was unable to be confirmed from the control column to the ailerons or from the rudder pedals to the rudder cables aft of the rear seat. Elevator continuity was not reported. The airplane had been purchased by the accident pilot approximately one month prior to the accident, and it was equipped with a Lycoming model O-360-A3A engine. According to the airplane's engine maintenance log on April 28, 2004 the engine had undergone a preservation process called "pickling." The process utilized 10 quarts of pickling oil and the engine was placed in storage. On May 9, 2006 the engine was drained of the pickling oil and replaced with 7 quarts of 50 WT oil. The cylinders were drained and cleaned, and then the engine was test ran. At the time of the installation the total time on the engine since new was 606.57 hours. The engine had undergone two other oil changes prior to the accident flight, the last oil change was accomplished during a conditional inspection on March 28, 2008, and at that time the engine had 646 total hours since new. Components of the engine were sent to the National Transportation Safety Board Materials Laboratory for analysis. The number 2 main bearing and piston had evidence of thermal damage consistent with the lack of lubrication. According to the engine manufacturer, it is possible that pickling agent can cause the lubricating channels to clog. The lubricating hole for the number 2 main bearing was melted shut and no residue cold be collected from the opening. The residue samples on other lubricated surfaces of the crankshaft and camshaft including other lubrication openings were collected and tested. The residue contained dimethyl amine, tetramethyl silane, and oxanilic acid, these compounds were not normally in the lubricating oil that was used on the accident airplane engine, however these compounds are often used in preservation fluids but are not unique to any particular type of product. The pilot held a private pilot certificate, with a rating for airplane single engine land. His most recent FAA third-class medical certificate was issued on March 27, 2007. The pilot’s logbook indicated that he had 58 hours of total flight experience, with 5 hours of total flight experience in the accident airplane make and model. The 1952 recorded weather at the Greater Cincinnati/Northern Kentucky International Airport (CVG), Hebron, Kentucky, located approximately 24 miles to the northwest of the accident site, included winds from 120 degrees at 4 knots, visibility 10 miles, few clouds at 8,000 feet above ground level, temperature 23 degrees C, dew point 10 degrees C, and an altimeter setting of 30.23 inches of mercury.
A loss of engine power due to oil starvation as a result of improper servicing (removal of preserving fluid) of the engine after it had been returned from storage.
Source: NTSB Aviation Accident Database
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