ENGINES
must to help minimize salt water corrosion. A down side is that if the fresh water is being supplied through galvanized pipe, impurities from the pipe can make their way into the engines. If at all possible, a de-mineralized/de-ionized fresh water source should be used. Another way to extend engine life is the addition of an airframe air fi lter. The old engine air particle separator (EAPS) fi lters that came with most aircraft did a good job on large particles but not on small particles. Most of our customers are using the barrier fi lter from Aerospace Filtration Systems, commonly known as AFS, with amazing results. This fi lters out the small particles and reduces erosion on the compressor blades and vanes, which increases the life of the compressor and maximizes engine output power.
Shiny Spot – Photo Courtesy of Premier Turbines
Aerospace Filtration Systems Barrier Filter – Photo Courtesy of Premier Turbines
HMM – How about any maintenance tips concerning hot and high operations? PT – Since engine start procedures are aff ected by altitude and temperature, engine fuel controls should be adjusted according to seasonal changes in temperature and when operating at higher altitudes. The automatic adjustment bellows in the fuel controls can only adjust so much, which is why a manual adjustment should be performed seasonally. Another lesson learned is on engine start procedures. Some pilots still push the starter button until they reach 18 percent N1 speed and then open the throttle. Commercial Service Letter (CSL) 1176 advises to open the throttle at 12 to 15 percent. This puts less stress on the fi rst stage nozzle and wheel and helps stop them from burning up.
No Shiny Spot – Photo Courtesy of Premier Turbines Last but not least is to reduce gearbox seal leakage with
the advent of the new generation synthetic oils. Before replacing the seal, if you look closely at the shaft where the seal is to be replaced, you will fi nd a shiny spot where the seal lip has been riding on the shaft. We recommend using Scotch Brite to remove the shiny spot. This better allows the seal to properly seat itself and minimize leakage and not burn the lip of the seal. We hope that you have enjoyed our trip down memory lane and this article. Another special thanks to Premier Turbines and its Rolls-Royce engine specialists. Let us know if you’d like to see an article on a specifi c topic.
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HelicopterMaintenanceMagazine.com December 2014 | January 2015
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