Show Low, AZ, USA
N4600Q
CESSNA 210K
The pilot reported that during cruise flight he observed an oil pressure reading of zero, followed about 4 minutes later by a total loss of engine power. He made a successful forced landing to an open meadow, which resulted in substantial damage to the engine’s firewall. A post accident examination of the engine revealed that the engine’s crankshaft and connecting rod bearings exhibited lubrication distress and thermal damage, and that the number 3 crankshaft main bearing exhibited lubrication distress. It was also observed that a gasket located between the STC oil filter adapter and the oil pump housing was displaced and contained dark stains. STC instructions require that after the oil filter adapter has been installed, to re-torque the adapter after 10 hours of operation. An airframe and power plant mechanic stated that he had re-torqued the oil filter adapter, but could not produce a record of the completed maintenance action.
On August 27, 2009, about 0730 mountain standard time, a Cessna 210K, N4600Q, sustained substantial damage during a forced landing after a loss of engine power about 6 nautical miles west of the Show Low Regional Airport (SOW), Show Low, Arizona. The airline transport pilot and his sole passenger were not injured. Visual meteorological conditions prevailed for the cross-country flight, which was operated in accordance with 14 Code of Federal Regulations (CFR) Part 135. A visual rules flight plan (VFR) had been filed but not activated. The flight departed the Flagstaff Pulliam Airport (FLG), Flagstaff, Arizona, about 0650, and was destined for SOW. In a written statement submitted to the Safety Board investigator-in-charge (IIC), the pilot reported that while in cruise flight at 9,500 feet mean sea level (msl) and after the engine oversped reaching the redline, he reduced propeller revolutions per minute (rpm) to the green arc and noted an engine oil pressure reading of zero. The pilot stated that he was about 20 nautical miles northwest of SOW when he declared an emergency. The pilot reported that about 2 minutes after observing the engine anomalies, the engine lost power, and about 2 minutes later “…[the] engine failed and seized, the propeller stopped, the oil filler door popped open, and smoke filled [the]cabin.” The pilot stated that he then picked out an open meadow and landed gear up. The airplane sustained damage to the engine’s firewall and belly skin. The airplane’s engine, a Teledyne Continental IO520L14, serial number 295481-R, was shipped to the facilities of Teledyne Continental Motors Analytical Department, Mobile, Alabama for examination. The examination was conducted by a Teledyne engine technician and overseen by a Federal Aviation Administration (FAA) inspector. The examination revealed that the oil sump contained a large dark stain and was covered with a gray epoxy substance. The engine had a Supplemental Type Certificate (STC), S.T.C. SE09356SC, oil filter adapter installed. A gasket located between the oil filter adapter and the oil pump housing was displaced and exhibited dark stains. Additionally, the bottom side of the engine’s vacuum pump’s housing was coated with a dark glaze, and when the pump was removed from the engine, oil was observed between the vacuum pump mounting flange and the gasket. The examination also revealed that the crankshaft exhibited lubrication distress, thermal damage, and mechanical damage. The connecting rod bearings exhibited varying degrees of lubrication distress and thermal damage, and the number 3 crankshaft main bearing also exhibited lubrication distress. A review of maintenance records revealed that the engine, manufactured on November 28, 2007, underwent a 100-hour inspection on August 20, 2009, at a total time of 352.9 hours. At the time of the accident the engine had accumulated 4.7 hours since its most recent inspection. A further examination of maintenance records revealed that on April 24, 2008, at a tachometer time of 160.0 hours, STC oil filter adapter, model C6LC-L was installed, which included 1 fiber gasket. In part, a review of the oil filter adapter’s installation instructions denotes the following: VII. Carefully slide the fiber gasket onto the oil transfer cylinder. Do not use gasket compounds or glues! VII. Thread the oil transfer cylinder into the oil screen housing. Position the oil filter adapter body to provide at least 3/8 inch clearance around the end of the oil filter. Toque the oil filter adapter to 65 lbs./ft.. XI. Verify oil quantity in accordance with the engine manufacturer’s instructions. Start the engine and check for oil leaks around the oil filter adapter and oil filter. If no leaks are detected, verify the engine manufacturer’s recommended oil quantity, replace the cowling in accordance to the airframe manufacturer’s installation instructions. Re-torque the oil filter adapter after 10 hours of operation! In an interview conducted by a FAA airworthiness inspector with the FAA certificated airframe and powerplant mechanic who performed maintenance on the airplane, the mechanic described the process to the inspector for the oil filter adapter’s installation, and when asked by the inspector what type of sealant he used, the mechanic responded that he used none, and that the STC called for the gasket to be installed dry. The inspector reported that the mechanic stated that he had accomplished the re-torque in compliance with the STC instruction, but that he could not produce a record of it. The inspector revealed that the mechanic mentioned to him during the interview that he had been “chasing an oil leak,” and that he had discussed with a Continental representative how to troubleshoot the source of the oil leak. The mechanic said that following the technical representative’s advice, he started to use RTV (Red or Black….he could not remember) on the oil pan to eliminate sources of the oil leak. The mechanic added that the RTV was not used on the oil filter adapter. The mechanic also reported to the inspector that he used a new gasket order from F&M Enterprises when he installed the engine and oil filter adapter.
A total loss of engine power due to the displaced oil filter adapter gasket, which resulted in an oil leak and oil exhaustion. Contributing to the accident was the unsuitable terrain for a forced landing.
Source: NTSB Aviation Accident Database
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