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October 14, 2020

It is no secret that fuel contamination can be extremely dangerous to your aircraft and cost a significant amount of money to the aviation business. Jet fuel contamination can cause the airplane to become grounded for an extended time resulting in substantial financial loss through lost revenue, treatment of contamination, and fuel tank repair.

Contaminated fuel also means trouble for an aircraft's engine and its fuel system components. Damage caused to them by contaminated fuel includes;

  • Corrosion in the fuel tank.
  • Clogging in the fuel filtration parts.
  • Component failure of aircraft fuel systems.
  • Blockage of fuel supply to the engines.

These hazards can lead to even more dangerous events in mid-air, and this is why it is crucial to make sure that the fuel in your fuel tank is free from any impurities. Understanding the common causes of fuel contamination will help prevent such accidents and prevent contamination from damaging your aircraft.

Below are the most common contaminants that can decrease the quality of the fuel in your aircraft.


Water is the primary cause of fuel contamination in aircraft fuel tanks. Water contamination can cause corrosion in the fuel system's components. When exposed to low temperatures, it can freeze up and clog various fuel filtration parts and fuel lines. If these lines are not unclogged immediately, they will halt the fuel supply to the engines.

Because of the fuel's unique composition, water accumulation in the tank becomes almost inevitable, especially when the aircraft is grounded. Even if the fuel's water content itself is low, there are multiple ways for moisture to become absorbed in it. Water in the fuel is present in the form of suspended particles or liquid state.

Moisture can become part of the fuel in various ways, these include:

  • The varying temperature inside the fuel tank can cause suspended moisture particles to become part of the fuel system.
  • For example, Warmer temperature allows fuel to absorb moisture from the humid atmosphere outside.
  • Lower and colder temperatures draw out suspended water particles from the fuel and accumulates them at low spots in the pipeline.
  • Moisture can also come from rainwater leaking past the seals in floating-roof tanks or moist outside air entering through the vents.

If water is not removed from the fuel, it can significantly degrade the fuel quality.


Although aviation fuels are sterile, the growth of microorganisms in fuel tanks becomes inevitable if air and moisture are present inside. If water is allowed to remain in the fuel for long, it will significantly promote bacteria and fungi' growth. These microorganisms feed on the hydrocarbons in the fuel and produce a sludge-like substance that can clog fuel filters. Some microorganisms also produce acid by-products that can accelerate metal corrosion inside the tank.


All particles suspended in the air, or fuel in this case (solid or liquid) are called particulates. Their contamination is dangerous for fuel and becomes part of it in different ways. Common particulates that contaminate the fuel are;

  • Sand and dirt particles getting in through open ports and vents.
  • Rust and corroding matter from different parts of the aircraft, even the fuel system itself.

Usually, these particles are filtered out by fuel filters. However, if their regular maintenance and inspections are not done, they can potentially clog various fuel system parts resulting in the blockage of fuel supply to the engine and, ultimately, causing the failure of the system.

About Acorn Welding

To ensure your aircraft is running on quality fuel, free from all kinds of contamination, or the fuel tank itself does not have any defects, Acorn Welding is here to help you.

At Acorn Welding, we promise nothing but the best. Our team of highly professional and well-trained aviation welders will make sure your fuel tank is in qualified hands for repair. For any further details, kindly visit our website or contact us at 1 888-388-8803.