Aviation Accident Summaries

Aviation Accident Summary LAX06FA091

Big Pine, CA, USA

Aircraft #1

N6034J

Cessna 182P

Analysis

The airplane impacted a hill about 34 miles north of the destination airport. The accident occurred under dark, nighttime, visual meteorological conditions. The airplane was en route on a 57-mile cross-country flight through a valley. The pilot frequently used the airplane to commute between the departure and destination points, accruing thousands of hours in the valley. The airplane wreckage was on a hill with about a 25-degree slope and located about 275 feet below the ridgeline's top. A heavily traveled highway was situated adjacent to the hill in the same north-south orientation as the route of flight. The wreckage distribution path was 400 feet long on a magnetic bearing of about 340 degrees. An examination of the impact ground scars disclosed that the airplane was in controlled flight in a near level configuration when it collided with the terrain. At the time of the accident, the moon was 3.7 degrees above the eastern horizon but blocked by mountains to the east. It is likely the lights from the automobiles on the highway would have been visible to the pilot, but there were no lights to distinguish the rising terrain. During the wreckage examination of the airframe's structure and the engine, no evidence of any preimpact failures or malfunctions was found.

Factual Information

HISTORY OF FLIGHT On January 17, 2006, about 2030 Pacific standard time, a Cessna 182P, N6034J, collided with a hill 7 miles south of Big Pine, California, in the Owens Valley. The pilot/owner was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, sustained fatal injuries; the airplane was destroyed. The personal local flight departed from Eastern Sierra Regional Airport, Bishop, California, about 2015, with a planned destination of Lone Pine Airport, Lone Pine, California. Visual meteorological conditions prevailed, and a flight plan had not been filed. A witness located at campground below the area of impact submitted a written statement to the Inyo County Sheriff. He reported that he was sitting in his car and noticed red and green lights faintly illuminated in the distance. He thought that the lights appeared to be at ground level and kept his eyes affixed as the lights became brighter and more distinct. The lights began to ascend and he discerned that they were part of an airplane. The airplane became closer and he could audibly distinguish the engine sound. The airplane collided with a hill east of the campground and burned. PERSONNEL INFORMATION A review of Federal Aviation Administration (FAA) airman records revealed that the pilot held a private pilot certificate with a rating for airplane single engine land. The original issuance date of his certificate was November 1982. The pilot's most recent medical certificate was issued as a third-class on May 29, 2005, and contained limitations that he must wear corrective lenses and possess glasses for near and intermediate vision. The pilot's personal flight records were not recovered. On his last application for a medical certificate the pilot reported a total flight time of 6,500 hours. The pilot's friends and family stated that he had attended a town meeting in Bishop the night of the accident and was flying back to his hangar in Lone Pine. They added that he frequently used the airplane to commute to Bishop and had accrued thousands of hours flying in the Owens Valley. AIRCRAFT INFORMATION No airplane or engine maintenance logbooks were located. A review was conducted of the material maintained by the FAA in the Aircraft and Registry files for this airplane. The single engine Cessna 182P, serial number 18263611, was manufactured in February 1975, and purchased by the pilot in November 2004. According to the original application for a normal category airworthiness certificate completed by Cessna Aircraft, a Teledyne Continental Motors O-470-S series engine (serial number 462155) was installed on the airplane at the time of manufacture. The engine found in the wreckage was an O-470-R series engine (serial number 131414-5-R), and was installed on the airplane on July 15, 1980. The National Transportation Safety Board investigator-in-charge (IIC) located an invoice from an engine overhaul that was completed on December 02, 1999. At that time the carburetor was additionally overhauled and bench tested. It is not known what maintenance was preformed after this. The IIC visited the pilot's hangar 2 days after the accident. A large rectangular fuel tank was found in a corner of the hangar. The easily accessible tank was equipped with a metering unit and dispensing nozzle. A sample of the fluid was taken that was found inside the tank. The odor was consistent with that automobile gasoline. A water detecting paste was exposed to the fluid and revealed no evidence of water. Lone Pine Airport personnel stated that they believed the pilot regularly used automobile gasoline in his airplane. They provided the dates of the last three purchases the pilot made for 100LL avgas at the airport: February 03, 2005: 13.82 gallons April 30, 2005: 41.20 gallons October 26, 2005: 10.10 gallons The airplane make and model is listed as being applicable to receive a Supplemental Type Certificate (STC) to operate on automobile gasoline. METEOROLOGICAL INFORMATION The closest weather observation station was at Bishop, located 23 nautical miles (nm) north of the accident site. A routine aviation weather report (METAR) was issued at 1956. It stated: winds 260 degrees at 4 knots; visibility 10 statute miles; skies clear; temperature 01 degrees Celsius; dew point -02 degrees Celsius; altimeter 30.10 inches of mercury. At 2056, the observation was updated to: winds 270 degrees at 5 knots; visibility 10 statute miles; skies clear; temperature -01 degrees Celsius; dew point -02 degrees Celsius; altimeter 30.09 inches of mercury. A Safety Board computer program was used to determine the position and illumination of the moon. At the time of the accident, the moon was 3.7 degrees above the eastern horizon on a magnetic bearing of 64.9 degrees. The program listed the disk illumination as 88 percent. Sunset and the end of civil twilight occurred at 1708 and 1736, respectively. A north-south oriented range of mountains were to the east, about 11 nautical miles (nm) from the accident site. The elevations reached 9,500 feet msl, which were 5,075 feet above the terrain of the accident site's elevation. The IIC calculated that the mountains were 4.34 degrees above that horizon at the accident site. A sergeant from the Inyo County Sheriff's Department responded to the accident immediate after being notified. He stated that at 2120, while en route to the accident site, he noted that the night was cold and dark. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was located on a 25-degree slope, comprised of soft dirt, low brush, and loose shale rocks. The accident site was about 23 miles from Bishop on a bearing of 153 degrees, and about 34 miles from Lone Pine on a bearing of 326 degrees. The global positioning satellite (GPS) coordinates for the crash site were 37 degrees 03 minutes 15.2 seconds north latitude and 118 degrees 15 minutes 51.5 seconds west longitude. The wreckage came to rest on a hill located between mountain ranges in an area known as Owens Valley. The valley stretches for over 75 miles between the Sierra Nevada Mountains on the west and the Inyo and White Mountains on the east. The mountains on either side of the valley reach above 14,000 feet mean sea level (msl), while the terrain floor averages about 4,100 feet msl, with sporadic hills located inside the basin. United States Highway 395 runs on a north-south route directly through the valley and is heavily traveled by both truckers and residents. The airplane came to rest about 4,700 feet msl, which corresponded to being about 275 feet below the ridgeline. The hill was surrounded by flat terrain, which the elevation was about 4,300 feet msl, and a campground was situated at the baseline. Highway 395 was located to the east of the hill, less than a mile from the campground. All of the airplane's major components were located at the accident site, with a majority of the debris within a 400-foot radius on a bearing of about 340 degrees. The first identified point of contact consisted of red lens fragments intertwined with broken and compressed brush. The main wreckage, consisting of the fuselage and empennage, came to rest upright about 400 feet from the first identified point of contact. Fire consumed the cockpit and cabin area. All flight controls were accounted for at the accident site. The upper portion of the fuselage was completely consumed by fire, with the floor area exposed. Both wings were located upslope, adjacent to the main wreckage. They were separated from the airframe and thermally damage on their inboard halves. The fuselage was extensively burned, with the only readily identifiable pieces consisting of the floor, seat tracks, control yokes, and rudder pedals. The firewall was imbedded under remnants of the right wing adjacent where the carburetor, gascolator, and fuel selector were located. All of the cockpit gauges were thermally destroyed. Both main landing gear wheel struts were present, with the right wheel still attached and intact and the left wheel consumed by fire. The right wing was separated from the fuselage, although the corresponding fuselage skin was thermally destroyed. It was positioned upside down with the aileron and flap control surfaces still attached at their respective hinges. The strut was still attached. The leading edge displayed crush deformation with the skin folded into itself giving an accordioned appearance. The left wing was separated from the fuselage, although the corresponding fuselage skin was thermally destroyed. It was positioned upside down with the aileron surface still attached at its respective hinges. The wing sustained aft crush deformation, with the leading edge skin folded into itself giving it an accordioned appearance. The crush began 56 inches inboard and increased gradually with the greatest crush deformation present in the most outboard portion of the wing, where it measured 25 inches aft. The engine was located about 930 feet downslope from the main wreckage. Several pieces had broken free from the engine and were found upslope near the natural fall line of the terrain. The engine had sustained crush deformation to several cylinders and rocker box covers. The propeller was found separated from the engine with both blades attached. The blades were both deformed aft, showing areas of leading edge polishing and gouges, with torsional "s" bending. Both tips were curled back with the remainder of the blade twisted. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot by the Inyo County Coroner's Office. The FAA Toxicology and Accident Research Laboratory performed toxicological testing of specimens of the pilot. The results of analysis of the pilot's specimens were negative for carbon monoxide or cyanide. Volatiles detected in muscle tissue were positive for ethanol (36 mg/dL,mg/hg blood; 15 mg/dL,mg/hg muscle; 37 mg/dL,mg/hg brain). The state of the specimens evaluated made it impossible to determine whether the ethanol was produced post-mortem or was a result of ingestion of alcohol. TESTS AND RESEARCH Investigators from the Safety Board, Cessna Aircraft Company and Teledyne Continental Motors examined the wreckage on scene. After recovery those Aircraft Recovery Service, Little Rock, California. Airframe: With the exception of the flaps, the flight control surfaces remained affixed to their respective attach points. Investigators accounted for the full length of the aileron cable circuit within each wing. In the right wing the aft cable was separated at the fuselage and the forward cable was separated at the control wheel pulley. The left wing forward aileron cable had separated at the control wheel pulley and the aft cable was separated at the fuselage. The aft cable ends were frayed and exhibited a broom straw appearance, consistent with that of overload. The forward cable ends retained the control wheel pulley attaching hardware. The right wing flap cables were accounted for with one separated at the left wing flap bell crank and the other separated near the fuselage at the turnbuckle. The remaining left flap cable was separated near the fuselage. The cables exhibited a broom strawed appearance at the separation points. The left flap control surface was located several feet from the wing. Investigators established continuity for the elevators and rudder control cables from the actual intact control surfaces to the remnants of the cockpit. The trim tab measured 1 7/16 inches, which the Cessna representative stated corresponds with a position of 5 degrees tab up. The flap actuator jackscrew was flush to the actuator body, which he said indicated that flaps were in the retracted position. The fuel selector was disassembled. The Cessna representative reported that the position of the ports corresponded to the valve being selected in the "BOTH" position. Engine: The Continental 0-470-RCS, serial number 131414-5-R, sustained impact damage and was found about 930 feet downhill from the main wreckage. The crankshaft flange was intact, with several propeller hub bolts stripped and one completely torn out. Most of the exhaust had separated from the engine. There were still exhaust pipes attached to the right side of the engine, where ductile bending and crushing was noted. Several rocker box covers were missing and cylinders were cracked open. One magneto was found in debris field and the other was not located. All spark plugs were examined with the exception of the top number 1 and bottom number 6 plug, both of which were not located. No mechanical damage was noted and the electrodes and posts all appeared similar. The top number 1 and both number 2 and 5 plugs had a light white coloration; the number 3 plugs were a dark gray; the number 4 plugs had an oily residue; the top number 6 plug was oily and contained debris. Investigators removed the cylinders, which revealed no evidence of foreign object ingestion or detonation. All valves were intact and the internal cylinder domes and piston crowns exhibited similar combustion deposits and coloration. Upon disassembly of the oil pump, investigators found the gears moved freely and no pitting, discoloration, or scoring was noted. The external casing of the carburetor appeared to have sustained thermal damage, with a dark soot layer over the surface. Investigators separated the casing revealing remnants of a melted substance inside, akin to a composite material. There was no carburetor float located inside the bowl. The inlet screen was removed and found to be clean. ADDITIONAL INFORMATION Continental released a publication stating their concerns for airplane owners using automobile gasoline in their engines. The manufacturer, "strongly advises against the use of such fuels for reliability and safety reasons. Because of this, engine or parts warranty will be voided where such fuels are used." They additionally stated that the "alcohol content of auto fuels may also result in damage to o-rings, seals, and other elastomer components in the fuel system." On June 04, 1998, the FAA Small Airplane Directorate issued a letter stating that, "there are numerous studies and technical reports available comparing auto gas to avgas for use in certificated airplanes and engines. The service history for airplanes and engines using auto gas has been good and is comparable to avgas." Petersen Aviation, Inc., and the Experimental Aircraft Association (EAA), the two sole owners of the automobile gasoline STCs, both state that the fuel should not be used if it contains methanol or ethanol. The alcohols are not compatible with materials in the fuel system and could result in a malfunction of the fuel delivery system. According to Petersen Aviation, Inc., all automobile gasoline sold in California contains ethanol with the exception of a few stations in San Francisco and Modesto. He added that bulk quantities of ethanol-free gasoline can be ordered. Neither STC holder could find evidence that the accident airplane held an STC for automobile gasoline. A representative from Exxon Mobil stated that all automobile gasoline delivered to that area of California contains 5.7 percent ethanol, regardless of the distributor or season.

Probable Cause and Findings

the pilot's failure to maintain an adequate terrain clearance altitude during a cruise descent that resulted in controlled flight into terrain (CFIT). Factors in the accident were the rising mountainous terrain, the dark nighttime lighting condition.

 

Source: NTSB Aviation Accident Database

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