Pickens, SC, USA
N138CK
CIRRUS DESIGN CORP SR-22
A few minutes after leveling the airplane at a cruise altitude of 9,000 feet mean sea level, the pilot felt the engine slightly vibrate or "wiggle." The propeller rpm then began to rise rapidly, and the pilot noted an engine oil pressure warning on the primary flight display. After unsuccessfully troubleshooting the engine problems, the pilot secured the engine and declared an emergency. An air traffic controller informed the pilot of an airport 4 miles from his location, and he turned the airplane toward that airport and prepared for an emergency landing. The pilot again unsuccessfully attempted to restart the engine and then resecured it while on the downwind leg of the airport traffic pattern. When the pilot turned the airplane toward the base leg of the traffic pattern at 1,200 feet, he added one notch of flaps, at which point, he felt the handling characteristics of the airplane change, and it began to feel "mushy." He then retracted the flaps, and the condition worsened. As the airplane descended through 1,000 feet, the pilot thought that he had "lost control of the airplane" and decided to activate the airframe emergency parachute. The parachute deployed, and, within seconds, the airplane settled into trees about 2 miles from the airport. The airplane remained suspended in the trees until emergency personnel arrived on scene and rescued the occupants. After the accident, the presence of oil was noted on the underside of the airplane. After the airplane was recovered from the trees, examination of the oil dipstick revealed small pieces of metal in the engine oil. Examination of the engine revealed that the crankshaft was fractured and that the crankcase exhibited varying degrees of fretting and lock-slot elongation on the main bearing supports, which is consistent with the application of insufficient torque on the cylinder through-bolts by maintenance personnel. New cylinders had been installed on the engine 113 hours before the accident. Because the cylinders were loose, the oil supply at the No. 2 main journal was shut off and the crankshaft broke, which resulted in the subsequent loss of oil pressure to the engine.
HISTORY OF FLIGHTOn July 22, 2012, at 1705 eastern daylight time, N138CK, a Cirrus SR-22, was substantially damaged during a forced landing in Pickens, South Carolina. The commercial pilot and three passengers were not injured. Visual meteorological conditions prevailed and an IFR flight plan was filed for the flight that departed Cobb County Airport-Mc Collum Field (RYY), Atlanta, Georgia, and was destined for Piedmont Triad International Airport (GSO), Greensboro, North Carolina. The business flight was conducted under the provisions of 14 CFR Part 91. According to the pilot, he began the day flying the airplane alone from Shelby County Airport (EET), Alabaster, Alabama to Gulfport-Biloxi International Airport (GPT), Gulfport, Mississippi, where he picked up 3 passengers. Prior to departure from GPT, the airplane was fueled "to the tabs" and 1 quart of oil was added to the engine. He and the 3 passengers then departed GPT, destined for RYY. As the airplane was descending enroute to RYY, the engine experienced a "brief misfire," which the pilot reported he had experienced in other airplanes before and was not concerned about. The airplane also experienced an ALT 2 failure enroute. The pilot attempted to troubleshoot the problem, without success, and then shed some of the electrical load. He continued to RYY and landed without incident. The landing at RYY was a planned fuel stop, enroute to the final destination of GSO, where the airplane was based. Prior to departure from RYY, the airplane was fueled with 60 gallons of 100LL aviation fuel, which again filled the tanks "to the tabs." The pilot checked the oil (about 6 1/2 quarts) and examined the engine and underside of the airplane for any abnormal conditions which would have explained the earlier engine misfire. He found no anomalies and proceeded with the departure. The takeoff from RYY was normal, and as the airplane climbed through an altitude of 800 feet, the pilot noted the oil temperature was "in the green" (about 190 deg) and the airspeed was about 130 knots. The pilot leveled the airplane at 9,000 feet, at a cruise speed of 165 knots. A few minutes later, the pilot felt a "wiggle," or a slight vibration from the engine. The prop RPM began to rise rapidly and he noted an engine oil pressure warning on the primary flight display (PFD). The pilot disengaged the autopilot, applied full mixture, and turned the fuel pump on. He also assured the magnetos were in the "on" position. The pilot thought he may have had a propeller overspeed condition, so he reduced the throttle; however, the RPMs remained high. He then secured the engine and declared an emergency with Greer Approach Control, with whom he had been communicating. The air traffic controller informed the pilot that Pickens County Airport (LQK) was at his "10:00 and 4 miles," and the pilot turned toward the field and prepared for a forced landing. He noted the RPMs were not decreasing as he pitched the airplane down for the descent (the airspeed was about 110-120 knots). The pilot attempted unsuccessfully to restart the engine, and then re-secured it while on the downwind leg of the traffic pattern for runway 23 at LQK. He believed he had plenty of airspeed and altitude, when he turned base at 1,200 feet, and added one notch of flaps. As the pilot added the flaps, he felt the handling characteristics of the airplane change, and it began to feel "mushy." He then retracted the notch of flaps and the condition became worse. As the airplane descended through 1,000 feet, the pilot felt as if he had "lost control of the airplane" and decided to activate the airframe emergency parachute. The parachute deployed and within seconds the airplane settled into the trees. The airplane remained suspended in the trees until emergency personnel arrived on-scene and rescued the occupants. PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate and a flight instructor certificate with multiple ratings including: instrument airplane, airplane single-engine land, and multiengine land. His most recent first-class medical certificate was issued on May 1, 2012. The pilot reported 1,800 hours of total flight experience, 350 of which were in the make and model of the accident airplane. AIRCRAFT INFORMATIONThe airplane was manufactured in 2009 and equipped with a Continental IO-550 engine. The following entries were noted in the airplane and engine logbooks: On April 28, 2010, all six cylinders were removed from the engine and sent to a repair station. According to the work order, maintenance to the cylinders included, "checking the guides and resealing the valves." The cylinders were reinstalled on May 4, 2010, and an operational check revealed no leaks or other anomalies. The most recent annual inspection was completed on the airframe and engine on September 1, 2011 at a tachometer time of 963 hours. No anomalies were noted during the inspection. On April 4, 2012, a new crankshaft seal and new cylinders were installed on the engine at a tachometer time of 1,252 hours. According to the logbook entry, an operational check was performed after installation, with no anomalies noted. The next entry in the logbook was on May 3, 2012. This entry described compression checks on all 6 cylinders with the following values: "1. 78/80; 2. 74/80; 3. 76/80; 4. 77/80; 5. 75/80; 6. 75/80." According to the entry, another operational check was performed with "no leaks noted." An oil change was performed on July 18, 2012. According to the logbook entry, the oil filter was cut and no metal was noted. The tachometer time noted at the accident site was 1,365 hours. AIRPORT INFORMATIONThe airplane was manufactured in 2009 and equipped with a Continental IO-550 engine. The following entries were noted in the airplane and engine logbooks: On April 28, 2010, all six cylinders were removed from the engine and sent to a repair station. According to the work order, maintenance to the cylinders included, "checking the guides and resealing the valves." The cylinders were reinstalled on May 4, 2010, and an operational check revealed no leaks or other anomalies. The most recent annual inspection was completed on the airframe and engine on September 1, 2011 at a tachometer time of 963 hours. No anomalies were noted during the inspection. On April 4, 2012, a new crankshaft seal and new cylinders were installed on the engine at a tachometer time of 1,252 hours. According to the logbook entry, an operational check was performed after installation, with no anomalies noted. The next entry in the logbook was on May 3, 2012. This entry described compression checks on all 6 cylinders with the following values: "1. 78/80; 2. 74/80; 3. 76/80; 4. 77/80; 5. 75/80; 6. 75/80." According to the entry, another operational check was performed with "no leaks noted." An oil change was performed on July 18, 2012. According to the logbook entry, the oil filter was cut and no metal was noted. The tachometer time noted at the accident site was 1,365 hours. WRECKAGE AND IMPACT INFORMATIONExamination of the airplane by a Federal Aviation Administration inspector revealed the airplane impacted trees about 2 miles from LQK. The airplane remained suspended in the trees during the inspector's examination; however, he did note the presence of oil on the underside of the airplane. After the airplane was recovered from the trees, examination of the oil dipstick revealed approximately 4 quarts of oil in the engine. There were also small pieces of metal noted on the dipstick. TESTS AND RESEARCHRecoverable Data Module (RDM) Examination The airplane was equipped with a Heads Up Technology Recoverable Data Module (RDM) mounted in the empennage, which was intended to record various flight and aircraft parameters. The device was retained after the accident, and forwarded to the NTSB Vehicle Recorders Laboratory, Washington, D.C., for data recovery. According to the RDM data, the engine lost power at 1659, and the airplane began a descent immediately after. The CAPS handle was pulled at 1704:55, and the CAPS rocket deployed at the same time. The last data points were recorded at 1705:20 Engine Teardown Inspection The engine was sent to Teledyne Continental Motors in Mobile, Alabama for a teardown inspection. The inspection revealed the crankshaft was fractured through the number 3 cheek between the number 2 rod journal and the number 2 main journal. The camshaft exhibited mechanical damage and was fractured in two places; forward of the second lobe and at the center of the second main journal. The crankcase exhibited varying degrees of fretting and lock slot elongation on the main bearing supports. The number 2 main bearing support exhibited signs of bearing rotation. Additionally, low torque values were noted for the cylinder through-bolts. No indications of fatigue were noted on any of the fractured components (For additional information regarding the engine teardown, see the Continental Motors Teardown Report and the FAA Inspector Teardown Report in the public docket for this accident).
A total loss of engine power due to the failure of the crankshaft, which resulted from the application of insufficient torque on the cylinder through-bolts by maintenance personnel.
Source: NTSB Aviation Accident Database
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