Kentwood, LA, USA
N93770
Cessna 210L
The airplane lost engine power while climbing to cruise through layers of clouds. Just after climbing through 8,000 feet, the instrument rated private pilot noted a momentary excursion in engine rpm. He noticed the engine oil pressure was indicating zero and pointed it out to the commercial pilot passenger. As soon as the passenger indicated he thought they should return to the departure airport, a "loud bang" was heard from the engine accompanied with smoke over the windshield and an "acrid smell in the cockpit." The pilot set up for a landing at an airstrip with the assistance from the passenger; however the cloud layers prevented them from seeing the airstrip. As the airplane neared the airstrip, the passenger yelled "trees," which the airplane impacted. A post-accident examination of the engine revealed the #1 and #2 connecting rods failed as a result of overheating from oil starvation. The reason for the oil starvation was not determined.
HISTORY OF FLIGHT On November 20, 2002, approximately 0720 central standard time, a Cessna 210L single-engine airplane, N93770, was destroyed when it impacted trees during a forced landing following a loss of engine power near Kentwood, Louisiana. The airplane was registered to and operated by Cloud Chasers of Hammond, Louisiana. The instrument-rated private pilot sustained serious injuries and the commercial pilot-rated passenger received fatal injuries. Marginal visual meteorological conditions prevailed on the ground at the time of the accident, and an instrument flight rules (IFR) flight plan was filed for the 14 Code of Federal Regulations Part 91 business flight. The cross-country flight originated from Hammond Municipal Airport, Hammond, Louisiana, at 0700, and was destined for the Grider Field Airport, Pine Bluff, Arkansas. According to the pilot's written statement, the pilot-rated passenger assisted him during the preflight inspection by checking the fuel and oil quantity. The passenger indicated to the pilot that there were 9 quarts of oil in the engine. After the preflight inspection and flight briefing, the pilot taxied to the departure runway and conducted an engine run-up and noted no discrepancies. The pilot obtained an IFR clearance from New Orleans departure control and departed runway 31. Shortly after the flight's last clearance to 8,000 feet msl and while flying above cloud layers, the pilot noted "a brief excursion of [engine] rpm." He asked the pilot-rated passenger if he noticed the excursion, and the passenger did not respond. The pilot checked the engine gauges and noticed the engine oil pressure was indicating zero. The engine oil temperature and cylinder head temperature were indicating in their normal (green) ranges. He pointed out the oil pressure gauge to the passenger and asked if he thought it was a bad gauge. The passenger indicated he thought they should turn back to the airport. About the same time the passenger opined about returning, a "loud bang" was heard from the engine accompanied with smoke over the windshield and an "acrid smell in the cockpit." The pilot knew the engine had sustained a mechanical failure of some sort, and had the passenger make a mayday call to air traffic control. The pilot trimmed the airplane for the best glide speed while the passenger searched the global positioning system (GPS) for the nearest airport. The air traffic controller suggested McComb Airport near McComb, Mississippi, which was approximately 28 miles away. The pilot reported they would not be able to reach McComb; however, the passenger found a "grass strip, 2,000 feet." The passenger provided a bearing to the pilot and indicated they were "too high." The pilot conducted a descending left turn in the clouds and requested the passenger call out final approach. The passenger called final approach and they both "tightened their seat belts," and the passenger unlatched the doors. During the approach, the pilot looked out the window and saw trees beneath them, but nothing ahead due to clouds and low visibility. The passenger called out trees and the pilot looked up and saw a "row of trees, like a picket fence." The airplane collided with the trees then impacted a dirt road beyond the tree line. After the impact, the pilot awoke with his face laying on dirt and pine straw, he unbuckled his seatbelt and felt his body fall slightly. He passed out attempting to reach his cell phone and awoke again in the ambulance that transported him to the hospital. Two hunters were hunting together on the Harrell Plantation Hunting Club property, which is where the accident site was located. The hunters reported hearing the airplane's engine "sputter" or "cutting off and on." Shortly thereafter, they heard the airplane crash. They searched and found the airplane and made a call to emergency responders. PESONNEL INFORMATION The pilot held a private pilot certificate with single-engine land and instrument airplane ratings. The pilot was issued a third-class medical certificate on June 26, 2001, with a limitation for corrective lenses. The pilot listed on the Pilot/Operator Aircraft Accident Report (NTSB form 6120.1/2) having accumulated a total of 225 hours, of which 14.3 were logged in the accident airplane make and model. The passenger held a commercial pilot certificate with airplane single and multi-engine land ratings, a single-engine sea rating and an instrument airplane rating. He held a second-class medical certificate that was issued on April 21, 2000. On the application for the medical certificate the pilot reported that he had accumulated a total of 1,100 flight hours. AIRCRAFT INFORMATION The 1974-model high-wing airplane (serial number 21060407) was equipped with a 285 horsepower Teledyne Continental Motors IO-520-L engine (serial number 295078-R) and a 3-bladed D3A32C-88MR McCauley constant speed propeller. The airplane was registered to the current owner on July 19, 1989. Review of the aircraft maintenance records revealed the airplane sustained gear-up landing damage on 4 separate occasions (1983, 1984, 1991, and 1998). The engine was overhauled and zero-timed at the Teledyne Continental Motor facility on May 25, 2000. The engine was then installed on the accident airplane on June 22, 2000, at an aircraft total time of 7,246.8 hours. An April 17, 2002, endorsement indicated the #2, #4, and #5 cylinders were removed due to low compression. They were sent to a repair facility, where the piston rings, exhaust valves, and exhaust valve guides were replaced. The paper work associated with the cylinder work indicated the cylinders were cleaned, inspected, honed, and deglazed. The valves and their respective seats were ground and the pistons were fluorescent penetrant inspected (Zyglow). This maintenance was performed at a tachometer time of 7955.0 hours, 276.2 hours prior to the accident. On September 4, 2002, the airplane underwent its last 100-hour inspection. At the time of the inspection the airframe had accumulated a total of 8,139.1 hours, and the engine had accumulated a total of 893.3 hours. During that 100-hour inspection, the engine oil was drained and the oil screen was inspected, with no debris noted. Ten quarts of oil was then added to the engine. At the time of the accident, the airframe had accumulated a total of 8,159.2 hours and the engine had accumulated a total 973.4 hours. METEOROLOGICAL INFORMATION At 0653, the weather observation at the McComb (Pike County) John E. Lewis Field Airport, McComb, Mississippi, (located 15 miles northeast of the accident site) reported the following weather conditions: wind from 200 degrees at three knots, visibility 2.5 miles in mist, a broken cloud layer at 500 feet, and overcast cloud layer at 1,900 feet, temperature 17 degrees Celsius, dew point 16 degrees Celsius, and an altimeter setting of 30.13 inches of Mercury. The remarks section of the observation stated that the ceiling was variable between 300 and 800 feet. At 0720, the weather observation facility at the Hammond Municipal Airport, Hammond, Louisiana, (located 25 miles southeast of the accident site) reported the following weather conditions: wind from 120 at 4 knots, visibility 5 statue miles in mist, scattered clouds at 1,200 feet, a broken layer at 3,600 feet, an overcast layer at 7,500 feet, temperature 17 degrees Celsius, dew point 17 degrees Celsius, and an altimeter setting of 30.13 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The airplane was located 0.92 nautical miles northeast of the Hurst Landing Strip. According to a GPS receiver, the accident site was located at 030 degrees 56.889 minutes north latitude and 090 degrees 36.616 minutes west longitude, and at an elevation of 316 feet. The wreckage path measured 180 feet in length from the initial contact with trees to the final component and was oriented along a measured magnetic heading of 195 degrees. The airplane traveled through a tree line that was approximately 100 feet thick. The outboard portion of the right wing, the entire right elevator, a portion of the left elevator and both wing tip caps were found along the distribution path within the tree line. The main wreckage included the engine and the fuselage, from the cockpit aft to the vertical stabilizer. The propeller separated from the engine and was found 25 feet forward of the main wreckage. The engine came to rest upright next to its mount. The engine displayed three holes in the crankcase. Two of the holes were on the top left side of the crankcase, above the #2 cylinder, and one was located on the right side crankcase above the #1 main bearing area. Oil was found on the front of the crankcase near the propeller flange bolts. Oil was also observed on the rear of the engine where the holes were observed in the crankcase. The oil screen was installed and was found safety wired. The oil filler cap and dipstick were found in place. The left magneto was found detached from its mounting pad. The remaining accessories were attached to their respective mounting areas. The engine was shipped to the manufacturer's facility for a detailed examination. A coating of oil was noted all along the bottom side of the airplane back to the horizontal and vertical stabilizer. TESTS AND RESEARCH The NTSB investigator-in-charge examined the engine at the Teledyne Continental Motors (TCM) facility in Mobile, Alabama, on November 22, 2002. One quart of oil was found in the oil sump. The spark plugs were removed and examined and the #2 top and bottom spark plugs were coated in oil. The other spark plugs displayed dark deposits and displayed "normal" wear patterns when compared to the Champion Check-A-Plug chart. Both magnetos revealed no anomalies. The engine's fuel system components were examined and no anomalies were noted. The engine's oil sump and oil pump were removed. The oil pump gears were intact and in place; however the pump gear cavity displayed rotational scoring "from hard particle passage." The oil pump relief valve had debris on its seat. The oil found in the sump was black and contained metallic debris (ferrous and non-ferrous) consisting of burned bearing debris, pieces of connecting rod and rod cap, and pieces of piston and piston rings. The oil sump gasket was intact and no leakage was observed. The #1 and #2 connecting rods were found separated at their crankshaft end, yet remained attached to their piston pin/piston. The #1, #2, #3, and #4 cylinder skirts were damaged. The #1 and #2 pistons were stuck inside their respective cylinders and had to be driven out manually. The #1 and #2 pistons displayed impact marks consistent with their respective intake and exhaust valves. The top of the #2 piston displayed a rounded crown top edge indicating the piston "had operated high in the combustion chamber." The #2 piston was missing a section below the lower scraper ring. Examination of the fracture surface by TCM metallurgists revealed the section separated as a result of an overload failure. Examination of the crankcase, near the rear of the #2 cylinder revealed an impression, which resembled one of the connecting rod nuts. Examination of the crankcase halves revealed no fretting at the main bearing support bosses or the backbone parting surface. No main bearing shift or tang slot elongation was observed. The main bearing surfaces were intact; however, the surfaces exhibited embedded aluminum debris. All main bearings appeared lubricated. The crankshaft front nose seal was in place and exhibited no evidence of leakage. The #1 and #2 connecting rod journals were partly melted "due to an oil starvation heating event." The #1 connecting rod oil feed hole was covered with melted steel pushing the oil transfer tube toward the #1 main bearing journal. The tube did not damage the rear main bearing. All of the connecting rod journals were damaged from "oil starvation." The #1 and #2 connecting rod journals were partly melted and black in color. The #3, #4, #5, and #6 rod journals were discolored. The #1 and #2 connecting rod pieces were found in the sump and were black in color. All fractures were damaged from post fracture impact damage. The original fracture surfaces that were still visible were examined under a microscope and appeared to be a result of overload. The #3 and #6 connecting rod bearings displayed heavy smearing damage, which was attributed to oil starvation. The crankshaft was then taken to the TCM materials laboratory to examine the crankshaft internal oil tube. All but the #1 connecting rod journal holes were open at their respective journals. A six-inch cotton swab was placed in the #2 connecting rod journal oil feed hole and was slid through the hole until the swab head was visible through the #2 main journal. No obstructions were noted. The swab was then placed in the #1 main journal oil feed hole and was slid through the hole toward the #1 connecting rod journal. The swab met the blockage at the end of the #1 connecting rod journal, and the swab protruded from the main journal hole approximately 3/8ths of an inch. The crankshaft was then sectioned longitudinally with to pass through the tube through its entire length. The blocked end was bisected, and was polished and etched. Examination of this section revealed only a "heat-affected zone of the plastically deformed journal material." No other obstructions were noted. ADDITIONAL INFORMATION The TCM 520-series engine oil supply is contained in the oil sump. The oil is drawn from the sump through the oil suction tube to the intake side of the engine driven, gear-type oil pump. From the outlet side of the pump, oil is directed to the integral oil filter screen chamber. From the oil filter discharge port, the oil is directed through a crankcase passage to the right crankcase oil gallery. Right side tappets, tappet guides and valve mechanisms are lubricated by passages leading off this gallery. Lubricating oil is directed to the governor drive gear and propeller governor through passages off the left main gallery. Oil is channeled through a discharge port to the crankshaft oil transfer collar and crankshaft interior. Oil then travels through a transfer plug installed in the inside diameter of the crankshaft and flows to the variable pitch propeller. Oil from the left main crankcase gallery is also directed upward through crankcase oil passages to the crankshaft main bearings. Oil flow from the rear crankshaft main bearing flows to the starter shaft gear bushing and idler gear bushing. Oil is then directed upward from the idler gear bushing to both accessory drive bushings. Oil lubricating the crankshaft main journals is directed through the upper main bearing oil holes, through crankcase passages to oil squirt nozzles that spray the crankcase side of the pistons and aids in lubrication and heat dissipation. Oil falls from the pistons through the crankcase cavity back to the oil sump. Oil flows from the main bearings through holes drilled in the crankshaft to the lower connecting rod bearings. Each of these holes through which the oil is fed is located so that the bearing pressure at that point will be as low as possible. The airplane was released to the owner's representative.
The failure of the #1 and #2 connecting rods during climb to cruise due to overheating, resulting from oil starvation. A contributing factor was the low cloud conditions limiting the pilot's visibility during the ensuing emergency landing.
Source: NTSB Aviation Accident Database
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