Plain English Meaning
Small filters in the fuel and oil lines that catch grit and water before it gets into the engine. Pilots are allowed to clean or replace them as routine upkeep.
Full Definition
Mesh or screen filtering devices installed in an aircraft's fuel and oil systems to trap dirt, water, sediment, and other contaminants before they reach the engine. They are removable for periodic cleaning or replacement and are listed by the FAA among items a certificated pilot may service as preventive maintenance on aircraft they own or operate (excluding those flown under Part 121, 129, or 135 operations).
Context Anchor
Seen during aircraft inspection and preventive maintenance, especially when checking, cleaning, or replacing items in the fuel and oil systems.