Tallapoosa, GA, USA
N5AW
CESSNA 177RG
The airplane was in cruise flight at 4,000 feet when the pilot declared an emergency due to low engine oil pressure and requested radar vectors to the nearest airport. The pilot received radar vectors to fly direct to the nearest airport. Shortly thereafter, the pilot advised the air traffic controller that he was unable to reach the airport and was going to land in a field. According to a witness adjacent the field, the airplane flew at a low altitude over his home, and it made a sharp, banking turn in an attempt to land in the field. The airplane was unable to land in the clearing and collided with a tree line at the end of a field, and a postcrash fire ensued. During the postaccident examination of the engine the left and right crankcase halves were found fractured between the No. 1 and No. 2 cylinder base pads. The No. 2 crankshaft journal was visible through the crankcase fracture, and no connecting rod was observed on the journal. Further examination of the No. 2 cylinder rod cap and the related bolt pieces revealed that the rod cap was fractured. Examination revealed that the bearing shells for the No. 3 and No. 4 cylinders displayed severe abrasive wear on the bearing surfaces. It is likely that due to the failure of the No. 2 rod end cap bolt, the rod end cap came loose, which resulted in a fracture of the case halves and subsequent loss of engine oil. After the loss of engine oil, the engine seized, which resulted in a total loss of engine power.
HISTORY OF FLIGHT On November 26, 2011, about 1333 eastern standard time, a Cessna 177RG, N5AW, owned and operated by a private pilot, was substantially damaged when it had a total loss of engine power and collided with trees in a field in Tallapoosa, Georgia. The certificated private pilot and two passengers were fatally injured. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91.Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed for the flight that departed the Knoxville Downtown Island Airport (DKX), Knoxville, Tennessee, destined for the Northwest Florida Beaches International Airport (ECP), Panama City, Florida. According to information obtained from the Federal Aviation Administration (FAA), the pilot was in cruise flight at 4,000 feet. He was in contact with the Atlanta air route traffic control center and declared an emergency due to low engine oil pressure. The pilot requested radar vectors to the nearest airport and was given a radar vector of 130 degrees to fly direct to West Georgia Regional Airport (CTJ), Carrollton, Georgia. The pilot advised the controller that he was unable to reach the airport and was going to land in a field. Shortly thereafter radar contact was lost and there were no other radio transmissions made by the pilot. According to a witness, the airplane flew at a low altitude over his home. The airplane made a sharp banking turn in an attempt to land in a corn field. The airplane collided with a tree line at the end of a field, and caught fire. The witness ran to the accident site and saw one of the passengers walking around outside the airplane. He recalled that the passenger was severely burned, but was alert. Shortly thereafter, emergency responders arrived at the scene. PERSONNEL INFORMATION The pilot, age 55, held a private pilot certificate, with ratings for airplane single-engine land and instrument airplane. The pilot's last FAA third-class medical certificate was issued on November 11, 2011, with limitations for near vision. The pilot reported 975 flight hours on his last medical application, and 50 flight hours within the last six months. The pilot’s current logbook was destroyed in the post-crash fire, and a determination of his current total flight hours and last flight review could not be verified. A review of the pilot’s last aviation insurance application revealed that on April 27, 2011, the pilot reported 915 flight hours total time, and 602 flight hours in make and model. AIRCRAFT INFORMATION The four-seat, high-wing, -gear airplane, serial number 177RG-0320, was manufactured in 1972. It was powered by a Lycoming IO-360A1B6, 180-horsepower, engine and equipped with a Hartzell model HC-C3YR-1RF constant speed propeller. Review of copies of the maintenance logbook records showed an annual inspection was completed January 1, 2011, at a recorded tachometer reading of 1034.2 hours, airframe total time of 5940.7 hours, and engine time since major overhaul of 813.9 hours. The tachometer and the Hobbs hour-meter were observed at the accident site; however, damage precluded determining the current readings. According to maintenance records provided by Zephyr Aircraft Engines, the engine had a cracked crankcase and was repaired at their facility on September 8, 2006. At that time they replaced the crankcase, through bolts, front main bearing, crankshaft gear bolt, and oil pressure relief ball. The engine-build records indicated that the connecting rods were not removed from the crankshaft at that time and that no cylinder work was performed. METEOROLOGICAL INFORMATION The reported weather at CTJ, which was located about 11 miles southeast of the accident site, at an elevation 1165 feet, at 1335, was: wind 170 degrees at 10 knots gusting to 15 knots, visibility 10 statute miles; scattered 2,900, broken 3,600, overcast 5,500; temperature 20 degrees Celsius (C); dew point 16 degrees C; altimeter 30.19 inches of mercury. WRECKAGE AND IMPACT INFORMATION The accident site was located about 11 nautical miles northwest of CTJ. The airplane came to rest in a flat attitude, on a course of about 006-degrees. Further examination of the wreckage revealed that the airplane came to rest in trees at the north end of a cleared field. The fuselage was consumed by a post-crash fire. The wing assemblies were fire damaged, and all flight control surfaces were accounted for at the accident site. The engine remained attached to the firewall and was fire-damaged. Examination of the cockpit and cabin section of the airplane revealed it was fire damaged. The instrument panel and instruments were fire damaged, and none of the aircraft instrumentation exhibited any reliable information. The flight controls were fire damaged and only the control cables remained. The fuel selector valve was not observed, and the area in the cockpit floor where the fuel valve is located was consumed by the post-impact fire. Examination of the left wing revealed that the left inboard section remained attached to the carry thru spar. There was post-impact fire damage observed on the inboard section of the left wing. The outboard six feet of the left wing was observed separated from the remainder of the wing. There was impact damage to the left aileron. The aileron and flap remained attached to the wing at all attachment locations. The left flap exhibited fire damage. Both the left and right aileron flight control cables were observed separated in a tension overload type separation. The flap actuator was measured at 2.2 inches, which equates to approximately 10 degrees of extension. The post-impact fire consumed the aft fuselage. The empennage and stabilator were observed burned. The vertical stabilizer and rudder were observed with impact and fire damage. The flight control cables from the empennage to the cockpit were intact and control continuity was established. The propeller assembly remained attached to the engine crankshaft flange and was fire damaged. The propeller was observed in a low pitch position and did not displayed signatures consistent with rotation at impact. Examination of the propeller spinner did not display signatures of rotation, and was crushed on one side. All three propeller blades exhibited discoloration and burned paint consistent with exposure to a post impact fire. The blade marked “A” did not reveal any damage signatures. The blade marked “B” was curved aft about 20 degrees. The blade marked “C” was bent aft about 45 degrees about 8 inches outboard of the hub. On site examination and a subsequent teardown of the engine revealed that the left and right crankcase halves were fractured between the #1 and #2 cylinder base pads. The #2 crank journal was visible through the crankcase fracture. No connecting rod was observed on the journal. The engine was disassembled to facilitate the examination. The crankshaft, crankshaft bearings, and camshaft were removed from the crankcase. The connecting rods and bearings were disassembled from the crankshaft. The lower rod bolt nut on the #1 connecting rod was observed to be backed off from its seated position about 1/8 inch. The upper nut was removed with little effort. One of the rod bolts was visibly stretched. The rod bearings exhibited radial scoring and thermal discoloration. The # 1 rod journal also exhibited light radial scoring and thermal discoloration. The #2 rod crankshaft rod end was separated from the crankshaft rod journal and impact damaged. Portions of the rod cap, rod bolts, and one rod nut were recovered from the crankcase. The #2 crankshaft rod journal was discolored and had some bearing material stuck to it. The #3 and #4 connecting rods remained attached to the crankshaft and the rod nuts were tight. The rod bearings exhibited heavy radial scoring. The associated crankshaft rod bearing journals exhibited radial scoring and thermal discoloration. The crankshaft front and center main bearings and bearing journals did not display any damage. Oil was observed on the bearing surface of the front main bearing. The rear main bearings exhibited light radial scoring and discoloration. The rear main bearing crankshaft journal exhibited thermal discoloration. The tappet faces exhibited indented wear marks consistent with the shape of the camshaft lobes. The oil pump gears did not display any damage. The fuel injector servo remained attached to the engine and was fire damaged. The servo fuel inlet screen was removed and no contaminants noted. The flow divider was fire damage and the rubber diaphragm was observed melted to ash when it was disassembled. The two-piece fuel injector nozzles were unobstructed. The engine driven fuel pump remained attached to the engine and was partially consumed in the post-impact fire. No fuel was observed in any of the engine fuel system components. The aircraft fuel strainer was not observed. The magnetos remained attached to the engine, exhibited thermal damage and could not be rotated by hand. The sparkplug electrodes exhibited dark gray coloration and worn normal condition. The #2 bottom sparkplug was oily. The ignition harness was fire damaged. The starter remained attached to the engine and was fire damaged. The alternator remained partially attached to the engine and was fire damaged. The vacuum pump remained attached to the engine and was fire damaged. The plastic drive coupling was burned. Metallic flakes were observed in the oil suction screen. The oil filter element was charred. No contaminants were noted between the folds of the oil filter element. The oil cooler was partially separated from its mounts and exhibited thermal discoloration. The oil cooler hoses were fire damaged. The #2 rod end cap/bolt and nut, #3 rod bearing and #4 rod bearing were retained and forwarded to the Safety Board’s Materials Laboratory, Washington, DC, for further examination. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was performed on the pilot on November 28, 2011, by the Division of Forensic Sciences, Georgia Bureau of Investigation, State of Georgia, as authorized by the Haralson County Coroner. The cause of death was reported as smoke and soot inhalation. Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report stated no ethanol was detected in the liver or the muscle, and rosuvastatin was detected in liver and blood. TESTING AND RESEARCH An examination of the #2 cylinder rod cap and related bolt pieces revealed that the rod cap was fractured through the middle and flattened at the cap piece. The bolt was fractured through the threads near the grip with the outer threads contained in the nut. The connecting rod bolt was fractured flush with the first engaged thread in the nut; two full threads remained on the grip portion of the bolt. The exposed shank of the bolt showed slight overall bending away from the rod journal. Magnified optical examinations found that the fracture had a smooth silky appearing surface except in one semi-circular area that was microscopically rougher. No identifiable macroscopic features were visible in the smooth area of the fracture. The fracture followed the thread root with a step connecting adjacent thread roots. The nut side fracture of the bolt was examined and some portions of the surface displayed directional fracture features. The deformation associated with the mark indicated a tangential impact direction on the nut that would apply a counterclockwise torsional force to the nut side of the bolt that was consistent with the direction of the shear dimples. The bearing shells for the #3 and #4 cylinders displayed severe abrasive wear on the bearing surfaces with some locations worn completely through the bearing layers exposing the underlying steel backing materials. The outer diameters of the shells were darkly discolored and areas of the bearing material showed melting. Both bearings showed signs of exposure to elevated temperatures.
The failure of the No. 2 rod end cap bolt, which resulted in a total loss of engine power.
Source: NTSB Aviation Accident Database
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