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service bulletins and service instructions for overhauling our turbochargers, valves, controls and wastegates, and replace all the required parts as indicated.The operative statement here is: “Follow the latest instructions and manuals...” So you need to talk with the overhauler and ask if they have and comply with all the manufacturer’s latest instructions before you consider their shop.Also, ask them for a detailed list of all the components they change during an overhaul. If they won’t supply one, move on to another shop. And if they do give you a list, pay close attention to whether or not they change critical components like the turbine wheel assembly.Components like the turbine wheel are subject to fatigue and thermal stress. And the effect of fatigue damage is cumulative, and not always obvious, which makes it very hard to detect during an inspection.For that reason, HET’s overhaul manual requires replacing critical components with new parts, which is the prudent course of action. It has proven to be the best way to help ensure that critical parts will make it through to the next overhaul cycle.Hartzell has also initiated a Recommended Service Facility (RSF) program. Participating turbocharger repair and overhaul facilities have agreed to follow the HET overhaul manuals and only use genuine HET parts. Currently, Quality Aircraft Accessories of Tulsa, Oklahoma (www.qaa.com) is an HET RSF, so if you’ve grown fond of your turbo and don’t want to trade it in, it would be a good idea to consider QAA.Another point to consider when making the new vs. rebuilt vs. overhauled decision is that new and, often times, rebuilt units will offer the benefits of having more new-generation components that are manufactured using the latest equipment, materials, and techniques. Plus, new and rebuilt units are covered by HET’s warranty.So, while the resulting new-generation turbocharging systems may not give you any more performance than the original units, the much-higher degree of precision will help ensure that, along with some judicious o•peration and preventative maintenance by you, today’s units will deliver years of safe, trouble-free performance. T&TSpecialized Aero Quarter Page 4/C AdSelect Airparts Quarter Page 4/C AdAbout Tim Gauntt, Director, Product Support, Hartzell Engine Technologies Tim Gauntt is the Director of Prod- uct Support for Hartzell Engine Technologies LLC.Tim has been active in the aviation industry for over 30 years as a general aviation mechanic, IA, AMT Part 147 instructor and various other technical support related positions.NOVEMBER 2016TWIN & TURBINE • 19