King Air Pilot

King Air Tips, Techniques and Travel Blog

What is sulfidation?

Written By: Doug Carmody - Oct• 16•14

Jet fuel contains sulfur. When it is burned at high temperatures it creates a gas called sodium sulfate. This gas mixes with the engine’s intake air. The intake air is contaminated with pollution, salt, soot and other nasty particles. This corrosive mix is what eats away at the compressor turbine blades. This process is called sulfidation.  As a pilot, mechanic or owner, it is in your best interest to stop this attack. The turbine blade manufactures have done their part. They create cobalt or nickel based turbine blades to withstand high operating temperatures. They coat the turbine blades with aluminide and silicone aluminide. All of this is an attempt to battle sulfidation.  So what can you do as a pilot? You could avoid flying in salt air near the ocean, deviate around industrial areas and avoid flying near cities. Obviously, you need more practical solutions. Pratt & Whitney recommends frequent engine washes especially if you operate within high salt environments such as near the coastline. Be sure to install intake and exhaust covers when you park the airplane overnight or longer. Only buy clean, filtered fuel. Make sure your fuel nozzles are operating efficiently.  These procedures help avoid contamination of the gas path of the engine. You may want to consider more frequent borescope inspections. Although this may increase short term maintenance expenses, it will pay off in the long run. Remember, if sulfidation reaches the base metal on the turbine blades, there is no stopping it.

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