Farmington, MO, USA
N5060V
Cessna 210L
While in cruise flight the engine crankshaft completely fractured and the propeller separated from the airplane subsequently striking the empennage. Witnesses reported that the airplane rolled to the right and impacted the terrain. The propeller severed the rudder control cables, the left horizontal stabilizer and elevator, and the vertical stabilizer. The engine crankshaft was fractured between the crankshaft oil seal and the propeller flange. The propeller flange remained attached to the propeller hub assembly. According to the NTSB Materials Laboratory Factual Report, "Bench binocular microscope examination of the fracture face revealed crack arrest marks typical of a fatigue cracking. The fatigue crack emanated from multiple origins at the external surface of the aft fillet radius from the propeller flange... ." The accident airplane had been involved in a propeller strike incident in which the propeller was damaged. The propeller was removed and sent for inspection and overhaul. According to the maintenance logbooks, a teardown inspection of the engine was not completed as required by Teledyne Continental Motors Service Bulletin SB-96-11. At the time of the accident the engine had accumulated 573.6 hours since the propeller strike event.
HISTORY OF FLIGHT On April 24, 2001, at 1345 central daylight time, a Cessna 210L, N5060V, owned and piloted by a commercial pilot, was destroyed during an in-flight collision with the terrain near Farmington, Missouri. Visual meteorological conditions prevailed at the time of the accident. The personal cross-country flight was operating under the provisions of 14 CFR Part 91 without a flight plan. The pilot and his single passenger were fatally injured. The flight departed Gallatin, Tennessee, at exact time unknown, and was en route to Potosi, Missouri, at the time of the accident. The airport manager for the Farmington Regional Airport (FAM) reported that he heard a distress call on the Unicom frequency and when he responded to the call he heard the sound of an engine surging. The airport manager stated that when he looked to the northeast he saw an airplane that appeared to be on a left base-leg for runway 20. The airport manager reported that the airplane suddenly banked 90 degrees to the right and then went straight down. A certified flight instructor (CFI) was flying near the Perryville Municipal Airport (K02), Perryville, Missouri, when he overheard a distress call on the Unicom frequency. The CFI reported, "Pilot requested Farmington Unicom to clear air traffic from the traffic pattern at Farmington, so that he could make a straight in approach to land. At that time, pilot also stated that he had an oil slick on his windshield. Within 5 minutes, I heard the pilot say 'this has now become an emergency.' The latter transmission was the last I heard from the pilot." The airport manager's and CFI's statements are appended to this factual report. Several witnesses to the accident reported that they heard a popping noise and saw the propeller separate from the airplane and strike the tail of the airplane. See attached Farmington Police Department Offense/Incident Report for copies of the witness statements. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for airplane single engine land, airplane multi-engine land, and instrument airplane operations. The pilot's last medical examination was conducted on August 17, 1999, and he was issued a second-class medical certificate with the limitation, "Must wear corrective lenses for near and distant vision." According to the pilot's flight logbooks, he had a total flight time of 5,285.4 hours, of which 4,268.8 hours were in single engine airplanes and 1,014.2 hours were in multi-engine airplanes. The pilot had flown 18.3 hours in the last 90 days, all of which were in the Cessna 210L. He had flown 13.5 hours in the last 60 days and 11.1 hours in the last 30 days. There were no flight logbook entries within 24 hours of the accident. AIRCRAFT INFORMATION The airplane was a Cessna 210L, serial number 21060828. The Cessna 210L is a single engine, high-wing, all-metal airplane of semimonocoque design. The Cessna 210L has a maximum seating capacity of six occupants. The airplane was issued a standard airworthiness certificate on May 10, 1975, and was certified for normal category operations. The airframe had accumulated a total flight time of 6,435.1 hours. The last annual inspection was performed on January 11, 2001, and the airplane had accumulated 21.8 hours since the inspection. The engine was a 300 horsepower Teledyne Continental IO-520-L, serial number 294667-R. The engine had accumulated 757.6 hours since the last major overhaul, which was completed on December 5, 1995. The last inspection of the engine was on January 11, 2001, and the engine had accumulated 21.8 hours since the inspection. The propeller was a three-bladed McCauley D3A32C88-MR, serial number 860222. The propeller had accumulated 573.6 hours since the last overhaul, which was completed on January 16, 1997. METEOROLOGICAL INFORMATION A weather observation station, located at FAM, about 1.7 nautical miles (nm) from the accident site on a 218 degrees magnetic heading, recorded the weather approximately 10 minutes after the accident as: Observation Time: 1355 cdt Wind: 010 degrees magnetic at 5 knots Visibility: 10 statute miles Sky Condition: Sky Clear Temperature: 17 degrees Celsius Dew Point: 04 degrees Celsius Pressure: 30.32 inches of mercury WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board's (NTSB) on-scene investigation began on April 24, 2001. The main wreckage was located behind a storage complex on East Karsch Boulevard in the city of Farmington, Missouri. A global positioning system (GPS) receiver recorded the position of the main wreckage as 37-degrees 47-minutes 00.06-seconds north latitude, 90-degrees 24-minutes 24.01-seconds west longitude. The propeller was located in a recreational park approximately 454 yards from the main wreckage on a 110 degree magnetic heading. A debris field, approximately 395 feet in length, began approximately 816 yards from the main wreckage on a 122 degree magnetic heading. The debris field contained fragmented portions of the empennage and aft fuselage structure. The aircraft was found inverted and nose down in a wooded area. All components of the airplane were accounted for between the debris field and the main wreckage site. The flight control cables were examined for continuity from the individual control surfaces to the main cabin area. Flight control cable continuity for the aileron and elevator control systems was confirmed. The rudder control cables were severed approximately five inches from the rudder horn. The landing gear was extended and the flaps were in the fully retracted position. There were multiple parallel slashes in the top fuselage skin moving aft along the dorsal fin into the empennage structure and components. The left horizontal stabilizer and elevator were completely separated from the empennage structure. The left horizontal stabilizer had a diagonal slash from the leading edge to the aft spar. The slash went through the lower and upper surfaces. The right horizontal stabilizer and elevator remained attached to the empennage structure. There was a slash at the inboard edge of the top skin of the right elevator. The vertical stabilizer and rudder were partially separated from the fuselage structure. Two of the three propeller blade tips were found in or near the empennage structure. The engine remained attached to the airframe structure. The engine was crushed aft into the firewall. The engine crankshaft was completely fractured between the crankshaft oil seal and the propeller flange. The propeller flange remained attached to the propeller hub assembly. The engine was sent to Teledyne Continental Motors for a teardown inspection. The results of the teardown inspection are appended to this factual report. The propeller was sent to McCauley Propeller Systems for teardown inspection. The results of the teardown inspection are appended to this factual report. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot at the Mineral Area Medical Center, Farmington, Missouri, on April 25, 2001. A Forensic Toxicology Fatal Accident Report was prepared by the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma, for the pilot. The toxicology results for the pilot were negative for all tests performed. TESTS AND RESEARCH Portions of the fractured crankshaft were submitted to the NTSB Materials Laboratory Division for examination. According to the Materials Laboratory Factual Report, "The crankshaft contained a fracture that intersected the aft fillet radius for the propeller flange and the cylindrical portion of the crankshaft located aft of the aft fillet radius." The report stated, "Bench binocular microscope examination of the fracture face revealed crack arrest marks typical of a fatigue cracking. The fatigue crack emanated from multiple origins at the external surface of the aft fillet radius from the propeller flange... ." The report further stated, "No evidence of corrosion damage was found at the fatigue origin area. Fatigue crack propagation was through the wall of the crankshaft and extended all around the circumference of the crankshaft." The report stated that there was no evidence of anomalies in the microstructure of the crankshaft metal. The nitride case extended from the surface to 0.04 inch below the surface and the Rockwell hardness was consistent with a nitride case. X-ray energy dispersive spectroscopy produced a spectrum consistent with the manufacture specified 4340 steel alloy. The NTSB Materials Laboratory Factual Report is appended to this factual report. According to an airplane mechanic who had worked on the accident airplane, N5060V had been involved in a propeller strike incident in which the propeller was damaged. The propeller was removed and sent for an inspection and overhaul. The mechanic reported, "The owner of Gallatin Flying Service, [name of owner], was informed and advised of the need to do a teardown of the engine to check for damage. He would not approve doing this. We [the maintenance staff] did a run out check on the crankshaft, aft of the propeller flange, with a dial indicator. No defects where noted at that time." According to the propeller maintenance logbook, the propeller was overhauled on January 16, 1997. According to the work order for the overhaul, the condition of the propeller blades was described as "wrecked blades". The overhauled propeller was reinstalled on the accident airplane on January 17, 1997. At the time of the accident the propeller had accumulated 573.6 hours since the overhaul. Copies of the propeller logbook and overhaul work order are attached to this factual report. According to the engine maintenance logbook, the engine was not inspected subsequent to the propeller strike event. A dial-out inspection, as reported by the airplane mechanic, was not documented in the engine maintenance logbook. At the time of the accident the engine had accumulated 573.6 hours since the propeller strike event. According to Teledyne Continental Motors Service Bulletin SB-96-11, dated September 10, 1996, the definition of a propeller strike is, "... any incident, whether or not the engine is operating, that requires repair to the propeller other than minor dressing of the blades ... or any incident while the engine is operating in which the propeller makes contact with any object that results in a loss of engine RPM." The service bulletin also stated, "Propeller strikes against the ground or any object, can cause engine and component damage even though the propeller may continue to rotate. This damage can result in catastrophic engine failure." The service bulletin states that, "Following any propeller strike a complete engine disassembly and inspection is mandatory and must be accomplished prior to further operation." A copy of Teledyne Continental Motors Service Bulletin SB-96-11 is attached to this factual report. ADDITIONAL INFORMATION Parties to the NTSB investigation included the FAA, Cessna Aircraft Company, and Teledyne Continental Motors. The main wreckage was released to a representative of the pilot's estate on May 10, 2001.
The fracture of the crankshaft due to fatigue, the propeller separating from the airplane while in-flight, which resulted in the propeller striking the empennage structure and flight controls, yielding the airplane uncontrollable. Contributing factors to the accident were the previous damage to the crankshaft, the company/operator management disregarding the engine manufacture's service bulletin mandating an engine teardown inspection after a propeller strike event, and the inadequate inspection of the engine by the company maintenance staff.
Source: NTSB Aviation Accident Database
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