Weatherford, TX, USA
N2644F
CESSNA 182J
The private pilot stated that, shortly after takeoff and while 300 to 500 ft above ground level, the engine experienced a loss of power when he activated the flap switch. The pilot troubleshot the loss of power and attempted to restart the engine; the engine restarted momentarily, then lost power again. The pilot did not pull the boost cutoff control. During the emergency landing, the airplane collided with a barbed wire fence and impacted several trees. An electronic engine monitor provided data from the accident flight. There were several noticeable voids in the engine monitor data, indicative of electrical power interruptions to the device. The final electrical power interruption occurred about the time of the accident. The investigation was unable to determine a reason for the electrical power interruptions to the engine monitor other than the cycling of the avionics switch. The airplane's electrical system could not be functionally tested due to impact damage. Four engine test runs were conducted, revealing no anomalies. During the tests, the battery voltage displayed 13 to 15 volts, and the ammeter did not show a discharge. Examination of the airplane revealed that the aftermarket supercharger drive belt was improperly installed upside down. The fuel inlet screen contained a small amount of multicolor organic material similar to tree leaves. The presence of organic material did not adversely affect the engine test runs, and likely was the result of the impact with trees during the accident sequence. According to the emergency procedures provided by the supercharger manufacturer, the supercharged engine can be operated during a loss of electrical power by pulling the boost cutoff control. Pulling the boost cutoff control results in gravity-fed fuel supplying the engine at un-boosted manifold pressure and allows operation as a normally-aspirated engine. Further, if the boost cutoff control is not pulled when electrical power is lost, surging occurs as the carburetor bowl empties and refills and will continue as long as fuel is available in the fuel system. The surging stops when the boost cutoff control is pulled. It is likely that, had the pilot pulled the boost cutoff control, the engine would have stopped surging and engine power would have been restored. The pilot stated he was not trained in the operation of the supercharger; however, the airplane flight manual supplement contained information regarding supercharger operation and emergency procedures.
HISTORY OF FLIGHTOn July 19, 2016, at 0903 central daylight time, a Cessna 182J airplane, N2644F, experienced a loss of engine power after departure and the pilot conducted a forced landing to a field near Weatherford, Texas. The private pilot and one passenger sustained minor injuries and the second passenger sustained serious injuries. The airplane sustained substantial damage. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight which was operated without a flight plan. The flight was departing from Parker County Airport (WEA), Weatherford, TX, and was en route to Pecos Municipal Airport (PEQ), Pecos, Texas. The pilot reported that he had departed from Denton Enterprise Airport (DTO), Denton, Texas, which was about 36 miles northeast of WEA. He landed at WEA and two passengers boarded the airplane while the engine continued to operate. He then taxied to the runway and noted that all the instruments showed normal operations, including the JPI engine data monitor (EDM) 700. He extended the flaps 10° for takeoff, increased the engine power to 29 inches of engine manifold pressure and 2,600 rpm, and lifted off at 60 to 65 mph. After takeoff, he retracted the flaps and noticed that the avionics turned off. He cycled the avionics master switch, but the avionics did not turn on again. About 40 seconds after takeoff while 300 to 500 ft above ground level, the engine experienced a loss of power. He attempted to troubleshoot the loss of power and to restart the engine; the engine restarted for about two seconds and then lost power again. The pilot did not remember if the engine ever experienced a total loss of power since he was concentrating on flying the airplane. He also did not remember if he ever pulled the boost cutoff control. He did not continue to troubleshoot the issue since his altitude was low and made a shallow bank towards a field for an emergency landing. During the landing, the airplane collided with a barbed wire fence, continued into a field, impacted several trees and came to rest on a road (figure 3). When the airplane came to rest, the pilot noted that fuel was pouring out of the fuel tanks all over the occupants. The pilot and two passengers exited the airplane. A witness, who was working in a field north of the accident site, stated that he heard an airplane engine overhead. He observed the accident airplane in a descent, apparently attempting to land in a pasture when it hit a fence in the middle of the pasture (figure 1). He called 911 and drove to the accident site. He observed three occupants who were already out of the airplane and noticed that fuel was pouring out of the wings onto the ground. The pilot stated to a Federal Aviation Administration (FAA) inspector, that one of the passengers recalled hearing the engine regain power just before touching down in the field. Figure 1 – Google Earth view of GPS track AIRCRAFT INFORMATIONA Forced Aeromotive Technologies (FAT) supercharger was installed on the airplane in May 2004 under supplemental type certificate (STC) SE10233SC and STC SA10232SC. On June 20, 2016, an annual inspection was completed at a tachometer time of 2,245.3 hours. During the inspection the maintenance personnel "checked and adjusted supercharger belt as per Force Air Tech service instructions." The pilot stated he was not trained of the operation of the supercharger by the manufacturer or the previous airplane owner after he purchased the airplane, nor was he required to do so. AIRPORT INFORMATIONA Forced Aeromotive Technologies (FAT) supercharger was installed on the airplane in May 2004 under supplemental type certificate (STC) SE10233SC and STC SA10232SC. On June 20, 2016, an annual inspection was completed at a tachometer time of 2,245.3 hours. During the inspection the maintenance personnel "checked and adjusted supercharger belt as per Force Air Tech service instructions." The pilot stated he was not trained of the operation of the supercharger by the manufacturer or the previous airplane owner after he purchased the airplane, nor was he required to do so. WRECKAGE AND IMPACT INFORMATIONThe responding FAA inspector reported that the left wing was folded over the top of the fuselage and the right wing was bent aft. The top of the cabin area had been opened and displaced aft. The fuselage was bent upward near the front seats (figure 2). Figure 2 – Accident airplane A postaccident examination of the airframe and engine was conducted by the NTSB Investigator-in-Charge (IIC), with technical representatives from Textron Aviation and Continental Motors, after recovery from the accident site. The engine was intact with no noticeable external damage. It was equipped with a FAT belt driven supercharger system that included two fuel boost pumps between the airframe fuel line and the engine carburetor. The top spark plugs and cylinder rocker covers were removed and the crankshaft was manually rotated with continuity confirmed to all cylinders and to the rear of the engine. The chromed cylinders were examined using a lighted borescope; all cylinder domes and pistons exhibited normal combustion deposits. All intake and exhaust valves were in place and free to move; suction and compression was confirmed in each cylinder. The magneto timing was checked and both magnetos were found to be timed at 22 ° before top dead center, which was normal timing. The top spark plugs exhibited normal wear signatures and dark deposits in the electrode areas. The air intake filter was clean and clear. The oil filter was in place and not damaged. The filter was opened and contained no debris or metal deposits in the filter element. The propeller remained attached to the crankshaft. Both propeller blades were bent and twisted aft and exhibited chordwise scratches and polishing. The cowl flap lever was positioned to OPEN. The carburetor heat control knob was full forward. The boost cutoff control knob was full forward and was not labeled on the instrument panel. The rudder and elevator flight control cables were continuous and undamaged. The left and right wings had been removed during the recovery process. The aileron flight control cables exhibited multiple overload separations. One portion of the left aileron control cable had been cut during the recovery process. The flap motor was energized with an external battery and operated the flaps normally. The flaps were found extended 10°. Due to impact damage and the displacement of the airplane during recovery the entire electrical system could not be functionally tested. An engine test run was conducted by the NTSB IIC and technical representatives from Textron Aviation, Continental Motors, and FAT. Prior to the test run procedures, the engine was examined. The gascolator screen was removed and was clean and clear of contaminants. The fuel inlet screen was removed from the carburetor and contained a small amount of multicolor organic material similar to tree leaves. The airplane had been stored outdoors at the storage facility. An external fuel source was connected to the airframe fuel line and the engine was started and test run several times. The engine operated at full power performance according to the STC operating specifications. The alternator inoperative and low fuel pressure lights were pressed and illuminated as expected. The lights did not illuminate during the engine test runs. The ammeter remained near zero and did not show a discharge. After the test runs were completed the carburetor was removed and examined. The carburetor was in place and not damaged. The throttle and mixture controls remained connected appropriately and were free to move. The unit was disassembled and the bowl was clean and clear. The floats and needle valve were attached and were free to move. The needle valve seat was clean and clear. Also following the test runs, the engine cowling was opened to facilitate further examination of the engine compartment. The supercharger drive belt was installed on the idler gear inside out. ADDITIONAL INFORMATIONFAT Supercharger Information The Airplane Flight Manual Supplement (AFMS) states that the supercharger supplies boosted engine induction air (figure 3) so it is necessary to boost fuel pressure to ensure an unimpeded flow of fuel through the carburetor. The two fuel pumps supply fuel to the carburetor at the required pressure. Either pump will independently supply sufficient fuel pressure for engine operation, but two are installed to provide backup in case of a pump failure. According to the STC manufacturer, as the fuel level in the carburetor changes, air flows in and out of the fuel bowl through a passage inside the mouth of the carburetor. When the supercharger is installed, this air passage becomes pressurized and at power levels above 1,700 rpm, the pressurized air in the fuel bowl pushes the fuel out and back to the fuel tank. The electric fuel boost pumps counter the air pressure so that the fuel enters the float chamber correctly. Figure 3 – FAT Supercharger Diagram The AFMS further states that in the event of a complete electrical failure (alternator or battery), the engine can be operated using gravity-fed fuel at un-boosted manifold pressure using the boost cutoff control. When the boost cutoff control is pulled, pressurized air from the supercharger is dumped into the engine compartment before reaching the carburetor. This lowers the carburetor's requirement for pressurized fuel and allows operation as a normally-aspirated engine. The STC owner added that, during a complete electrical system failure, the effect would be the same as turning off the fuel boost pumps. With the fuel boost pumps off and engine power above 1,700 rpm, the carburetor fuel bowl would empty in 5 to 10 seconds. With the fuel bowl empty, the engine would begin to lose power; as the engine rpm decreases the supercharger boost also decreases and fuel begins to enter the fuel bowl again. The engine power would surge back and the cycle would repeat. The whole cycle would take less than 10 seconds and would continue as long as fuel was available in the fuel system. The cycle could be stopped by pulling the boost cutoff control. If the engine cannot be restarted during an engine failure the boost cutoff control should be pulled. According to the AFMS, the maximum manifold pressure is 28 inches of mercury. The boost cutoff control is used only in emergency situations whenever both fuel boost pumps become inoperative. Engine Failure Procedures If the engine failure in-flight procedures are unsuccessful in restarting the engine, and the low fuel pressure light is illuminated, the AFMS states the following: Boost Cutoff – Pull Fully Mixture – Full Rich Propeller – Full Throttle – Full Power – See Warning Below Follow in-flight low fuel pressure procedures to land as soon as practical WARNING: To increase power, use the throttle first. When full throttle is reached and more power is needed, slowly push in the boost cutoff control, but no not exceed boost cutoff manifold pressure limitations. To decrease power, pull the boost cutoff control first. When boost cutoff control is out fully and a further reduction in power is needed, use the throttle control to reduce power. If this is not followed, engine power fluctuations may occur. If power fluctuations do occur, pull boost cutoff control out fully and apply full throttle, then continue making power changes as described above. Excerpts from the AFMS can be found in the public docket associated with this accident report. JPI Engine Data Monitor (EDM) 700 The EDM was downloaded by the NTSB Recorders Laboratory. The recorded data revealed that the engine parameters were all normal. There were several noticeable voids in the data indicative of electrical power interruptions to the device. The final electrical power interruption occurred from 09:01:47 to 09:04:37, which was during the time of the accident. The EMD was downloaded again after the engine test runs. The data did not reveal any anomalies and the battery voltage was 13 to 15 volts, which is a normal voltage. Garmin Aera 796 GPS The GPS was downloaded by the NTSB Recorders Laboratory. The recorded data revealed 12 sessions, which included the two flights on the accident day. The accident flight data was plotted for geographical representation (figure 1).
An electrical system malfunction for reasons that could not be determined, and the subsequent loss of engine power due to the loss of the electrical boost pumps. Also causal was the pilot's improper emergency action following the loss of engine power due to his lack of knowledge regarding the engine’s supercharger system.
Source: NTSB Aviation Accident Database
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