Airplane Used Oil Analysis

Engine oil serves as a lubricant and coolant in our airplane engines. In addition, the airplane oil carries dissolved metals that occur through normal wear and tear. When we discard used oil, we are discarding a wealth of information about the state of engine wear, along with important clues about pending engine failure!

What does Airplane Oil Analysis tell us?

By analyzing exactly what is present in the oil and comparing it against past readings, one can gauge relative engine health and narrow down any problems to certain components.

Different components in the engine are composed of different elements.  You can find aluminum in pistons and engine cases and iron in rotating shafts. Lead is prominent in bearing surfaces, though a high lead reading in planes running avgas is normal due to lead content in the fuel. High lead in a pane running auto gas, however, can be a problem.

Some elements, such as silicon, can be introduced from outside of the engine and a high silicon reading can indicate a poorly functioning air filter, letting sand (mostly silicon) in the engine.

Take a look at these sample Oil Analysis reports, along with an explanation on the problems identified:

Sample Piston Report 1

Sample Piston Report 2

When to get airplane oil analysis

To detect trends, aircraft used oil analysis data is most useful when analyzed as part of a series. Therefore, we recommend getting a sample analyzed for every oil change. Contact Brian in maintenance to add this service as part of your routine maintenance at Monticello Aviation.