Advance, NC, USA
N162US
CZECH SPORT AIRCRAFT A S SPORTCRUISER
According to the pilot, about 45 minutes into the local flight and after reducing engine power for the descent, the engine rpm began to decrease. She applied carburetor heat in an attempt to regain full engine power; however, the engine rpm continued to decrease, and the engine then lost total power. She unsuccessfully attempted to restart the engine, performed the emergency engine shutdown procedures, and then chose to land the airplane in a field, during which it sustained substantial damage to the firewall, fuselage, and right wing. A postaccident examination of the airframe revealed no anomalies that would have precluded normal operation. The engine was test run and examined about 4 months after the accident. The engine was initially test run using alternate fuel with no anomalies noted. The engine was then test run using fuel found in the left wing tank. During that test run, the engine hesitated, but it did not lose total power. The fuel recovered from the airplane was tested, and it did not meet the specification limits for automotive gas, aviation gas, or UL82 aviation gas; however, it did exhibit characteristics of evaporated automotive gas. Although a white powdery substance was found in the carburetor and the fuel did not meet specifications, due to the amount of time that passed between the accident and the engine examination, it could not be determined whether the powdery substance was in the carburetor, or what the fuel condition was, when the engine lost power. Weather conditions at the time of the accident were conducive to the accumulation of serious carburetor icing at glide power, and carburetor icing is more likely to form when an engine is operating on automotive gas. In addition, the Pilot's Operating Handbook noted that carburetor heat should be used during descents. Therefore, it is likely that the pilot's delayed application of carburetor heat during the descent resulted in a total loss of engine power due to carburetor icing.
On May 4, 2014, about 0930 eastern daylight time, a Czech Sport Aircraft Sportcruiser, N162US, performed an off airport landing in a pasture near Advance, North Carolina. The private pilot sustained serious injuries. The airplane sustained substantial damage to the right wing, fuselage, and firewall. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. The airplane was registered to Sugar Valley Airport and operated by an individual under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight.In an interview with a Federal Aviation Administration (FAA) inspector, the pilot stated that while in flight, she performed several flight maneuvers. About 45 minutes into the flight she decided to prepare to land and at 1,800 feet above ground level (agl) she reduced the engine power in order to descend. Then, about 900 feet agl the engine rpm began to decrease. The pilot applied carburetor heat in an attempt to regain engine power: however, the engine rpm continued to decrease and then it lost total engine power. She unsuccessfully attempted to restart the engine, performed the emergency engine shutdown procedures, and then elected to land the airplane in a field. During the landing, the airplane impacted the ground, which resulted in substantial damage to the firewall, fuselage, and right wing. A postaccident examination of the airplane by a FAA inspector revealed that the airplane initially impacted the ground approximately 45 feet from where it came to rest. About 12 gallons of fluid similar in color and smell to automotive gas was noted leaking from the airplane. In addition, control continuity was established from the cockpit to the rudder, elevator, and left aileron. Control continuity could not be determined to the right aileron due to impact damage to the right wing. The propeller was examined and no scoring or bending was noted. According to the airframe maintenance records, the airplane was manufactured on June 8, 2011. It was equipped with a Rotax 912 ULS series, 100 hp engine. The most recent conditional inspection was performed on January 7, 2014, at a total time of 1157.8 hours. The most recent engine inspection was performed on January 7, 2014, at an engine total time of 50.0 hours. The hobbs meter on the airplane indicated a total time of 1183.0 hours of total time at the time of the accident. In addition, the pilot's operating handbook stated that "the maximum amount of ethanol blend is defined as follows: E10 (Unleaded gasoline blended with 10% ethanol) In addition to AVGAS and unleaded automotive fuel (Mogas), the Rotax 912/914 series of engines are now approved for use with E10." According to the FAA inspector's report, the airplane was purchased by Sugar Valley Airport on April 19, 2014. According to a flight log kept by Sugar Valley Airport personnel, the accident flight occurred on the fifth flight, and was about 6 flight hours, after the airplane was purchased. In addition, the airplane was fueled with 12.8 gallons of fuel the day before the accident and then fueled just prior to the accident flight. In the interview the pilot stated that she departed the airport with 30 gallons of automobile fuel and flew for approximately 45 minutes prior to the engine experiencing a total loss of engine power. According to an individual at the departure airport, he stated that the fuel used to fill the airplane was obtained from a local gas station and was 93 octane fuel. A review of recorded data from the Davidson County Airport (EXX), Lexington, North Carolina, automated weather observation station, revealed that around the time of the accident wind was 250 degrees at 3 knots, 10 miles visibility, clear skies, temperature 19 degrees C, dewpoint 10 degrees C, and an altimeter setting of 30.02 inches of mercury. An engine examination was performed on August 28, 2014, at a salvage facility in Griffin, Georgia. The engine was examined and valve train continuity was confirmed when the propeller was rotated by hand. In addition, thumb compression was confirmed on all cylinders. The right side carburetor bowl was removed and a white fluid was drained. A white paste was present in the bottom of the carburetor that also covered the main jet in the carburetor. The fluid was tested with water-finding-paste and it did not contain water. The left side carburetor bowl was removed from the engine and white powder was noted in the bottom of the bowl. No fluid was noted in the bowl. The mechanical fuel pump was removed from the engine and a small amount of fluid was drained from it. There was no fuel in fuel lines to or from the fuel pump. The fluid drained from the fuel pump was orange brown in color and contained grainy material. In addition, the gascolator was removed and did not contain fluid. During the on-scene portion of the investigation, an FAA inspector removed the gascolator and drained the fluid into a container. The gascolator exhibited impact damage and was dented. The screen was examined and no anomalies were noted. All spark plugs were removed from the engine and exhibited normal wear when compared to the Champion Spark Plug Check-a-plug chart. The spark plugs were replaced in order to facilitate the engine run. Alternate fuel was pumped into the engine and a spare battery was utilized to start the engine. When the engine started, the engine driven fuel pump, electric fuel pump, carburetors, oil pump, and engine cooling system all operated without anomalies. Then, the fuel contained in the left wing of the airplane was pumped into the engine and the engine was started. After it started, the engine did not run smoothly and hesitated several times. A powder substance that was found in the carburetor prior to running the engine was captured and sent for testing in the NTSB Materials Laboratory. The results indicated that the substance was similar to sulfated alkanol amide, which was a type of material found in surfactants, which are typically found in fuel system and carburetor cleaners. A substance library search found that the unknown powder's chemical makeup was similar to several known surfactants makeup; however, no strong match was found. A fuel sample was taken from the left wing of the airplane and sent for testing. The results revealed that the fuel did not meet specification limits for Motor Gas, Avgas, or UL82 Avgas. However, it exhibited characteristics of Motor Gas that had evaporated. The carburetor icing probability chart from FAA Special Airworthiness Information Bulletin (SAIB): CE-09-35 Carburetor Icing Prevention, June 30, 2009, shows a probability of serious icing at glide power at the temperature and dew point reported at the time of the accident. According to the SportCruiser Pilot Operating Handbook, it stated to "use carburetor heating [in a] long time descent and in area of possible carburetors icing." According to "The Use of Automobile Gasoline (MOGAS) in Aviation," a publication produced by Transport Canada, it stated that "the likelihood of carb icing while flying on mogas is higher. Although the severity of the carb icing and the methods to deal with it are similar for both Avgas and Mogas, its onset is likely to occur at higher ambient temperatures and a lower humidity with Mogas. In other words, conditions under which a pilot may feel there is only a slight risk for carb icing on Avgas may in fact be ideal for the formation of ice while using more volatile Mogas. This will result in the need to select 'carb heat on' in less severe icing conditions and for a longer duration while using Mogas."
The pilot’s failure to apply carburetor heat during a descent with reduced engine power while operating in conditions conducive to carburetor icing, which resulted in a total loss of engine power.
Source: NTSB Aviation Accident Database
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