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upon to operate at speeds over 100,000 RPM and at temperatures exceeding 1,650o (F).Contrary to popular belief, although the turbocharger does convert waste energy (in the form of hot exhaust gasses) into additional ‘power’, the system is not a power source itself. The compressed gasses produced by the turbocharger increase the density of the fuel/air mixture, which in turn, increases the engine’s power output at higher density altitudes.As I stated earlier, your aircraft’s turbocharger system is very complex and operates at extreme speeds and temperatures – two conditions that just go looking for problems. But the good news is, moretimes than not, you will get indicators of somepending problem before it becomes critical.Typically, you will get nuisance-related maintenance items, such as a bit of extra oil consumption, a slight leak, a bit of blue smoke from the exhaust, or possibly oil collecting at the exhaust outlet. These are just some of the visual indications that something is not performing as it should.I routinely remind pilots that a thorough pre- flight is the time to look for these clues. Keep in mind that some of the warning signs arevery subtle and easy to miss. Take yourtime. If you see something you’re not used to seeing, you need to get it looked at by a mechanic.Another highly-effective practice is for owner/ operators to be very proactive in their maintenance. Since the turbocharger shares the oil system with the engine, you should routinely change the oil at 25 or 35 hours. And, like other parts of the engine, the condition of the oil can provide an indicationof the health of the turbocharger.During the oil change, the owner or mechanicshould take the opportunity to give the entire turbocharger system a good inspection. Keep the air filter clean and check the security of the intake and alternate air systems to prevent FOD (foreign object debris) from entering the compressor or from robbing the compressor of air. Also, take time to visually inspect all clamps, hoses, ducts and related components of the intake/exhaust system.The bottom line is: Knowing your engine’s typical operating parameters and recognizing differences can help eliminate costly repairs down the road.Before All Else Fails, Follow The Instructions...One simple way you and your mechanic can help ensure that your turbocharger system gets you to TBO is to read and follow the Pilot’s Operating Handbook (POH).In particular, I mean the section that covers the proper turbocharger cool-down procedures for your aircraft.The number one enemy of the turbocharger system is heat build-up, and that heat comes in the form of lack of oil, lack of cool oil, hot exhaust and poor power management. As a general rule, all turbocharged engines should be ‘idled’ for a specific time and power setting to cool the system before shutdown after landing or engine maintenance operations.Properly following this procedure will prevent two bad things from happening: The first is the continued high-speed rotation of the turbo without adequate oil flow. The second is the development and build-up of abrasive carbon deposits in the oil. (a.k.a. coke).Remember that the system’s lubricating oil is coming directly from the engine’s oil system, so shutting down the engine immediately stops the flow to the turbocharger. Most Hartzell turbochargers use full- floating hydrodynamic bearings. Hydrodynamic bearings provide outstanding performance in constant-speed applications, like we have in aircraft installations, but if the turbocharger is still turning at a high rate of speedNOVEMBER 2016TWIN & TURBINE • 17