AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

What Does an Aircraft Fuel Strainer Do?

To ensure the fuel received by an engine is safe and free of contaminants, aircraft employ the use of fuel filters and strainers. All aircraft require filters for their fuel, but the demands of a particular engine will vary by size and configuration. Larger and higher-performance aircraft have higher demands to function; while some filter styles may suit light aircraft, other designs are needed for turbine jets and twin engines. As a result, there are many styles of aircraft fuel strainers on the market, and procuring the correct style is crucial for the safety of your aircraft. That being said, all strainers serve the same purpose of trapping debris from aircraft fuel to make sure it is clean enough for use. This blog will serve to offer a better understanding of the purpose of an aircraft fuel strainer and the types available for different categories of planes.

Smaller and less demanding applications may make use of what is known as a finger screen. Screwed into a fitting that has been welded into the tank outlet, these filters increase the surface area of the outlet and permit large amounts of filtered fuel to exit the tank. A finger strainer gets its name from its finger-like shape; the long tube protrudes into the tank and catches any debris in its fine netting. While the strainers in most systems are similarly designed, their placements vary. One example of this is in in-tank boost pumps where the tank outlet strainer is situated at the inlet to the pump.

Other tank systems that employ different fuel strainer configurations are carburetor and fuel-injection systems. These require an additional main strainer between the fuel tank outlet and the fuel metering device. On lighter aircraft that operate with fuel-injection systems, the main strainer might come in the form of a gascolator, that of which is a filter that incorporates a sediment collection bowl. Typically, these bowls are fabricated from glass to allow for quick visual inspections of the contents, but opaque bowls are also common. Regardless, routine removal and draining is required.

In higher-performance and twin engine aircraft, a main strainer is used for each engine, often mounted low on the engine firewall. Other larger fuel filters have a double-screen construction where one cylindrical screen is wrapped with another fine mesh material. For aircraft that run on turbine engines, the quality of the fuel must be extremely high, as these systems are sensitive. In such applications, micronic filters should be used to filter out microscopic contaminants. One example of this type of filter is a changeable cellulose filter mesh used to block particles from 10-200 microns in size. Moreover, it is extra important when using smaller filters to be cautious of blockage.

In addition to the strainer, tanks will also employ the use of a sump to filter their fuel. This component is located at the bottom of a fuel tank, below the outlet. With some type of screen used for filtering, the sump traps the bigger contaminants that sink to the bottom of the tank. When filtration systems are functioning properly, the system should display ideal differential pressure that can be monitored from the cockpit. As having a functioning filtration system is crucial to clean and safe operations, be sure to only source any parts you need from a reputable distributor like Fasteners 360. Owned and operated by ASAP Semiconductor, we make quality the cornerstone of our operations, and we offer around-the-clock service for our loyal customers. Contact us at any time or submit an Instant Request for Quote form to begin the process of obtaining your high-caliber aircraft filters and more!


August 9, 2022

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