Airline Transport Pilot Written Knowledge Practice Test

Using lower quality fuel in an aircraft engine can lead to excessive oil consumption due to several factors associated with fuel impurities and combustion characteristics. Lower quality fuels may contain higher levels of contaminants, which can lead to incomplete combustion. This results in the formation of carbon deposits on the piston rings and inside the combustion chamber. These deposits can cause the engine to work harder, leading to increased oil consumption as the engine struggles to maintain performance despite the lower efficiency of the fuel being used.

Additionally, inferior fuel may not have the appropriate properties for lubricating and protecting engine components, which can exacerbate wear and cause the engine to consume oil at an accelerated rate. Overall, using lower quality fuel places the engine at risk for a variety of issues, making excessive oil consumption a likely outcome.