The PTI 21-11655 is an FAA-PMA approved fluid filter element designed for aircraft hydraulic and hydrocarbon fluid systems. It is commonly used in Bell helicopter applications (e.g., 212 and 214ST series) where it serves as a replaceable element inside a dedicated filter housing to remove particulate contamination from fuel/oil or hydraulic fluid circuits.

The element uses a pleated filtration media design (often stainless steel mesh or high-efficiency synthetic media depending on configuration), allowing stable flow with high dirt-holding capacity. It is designed for outside-to-inside flow direction, ensuring contaminants are captured on the outer surface of the media for efficient filtration and maintenance inspection.

This filter is a reusable-type element in some configurations, meaning it can be cleaned and reinstalled depending on maintenance specifications, or replaced during scheduled overhaul intervals. It is engineered to meet aviation requirements for pressure drop, flow stability, and contamination control in critical aircraft systems.

Key features include:

PTI part number: 21-11655
FAA-PMA approved fluid filter element
Used in Bell helicopter systems (e.g., 212, 214ST)
Designed for fuel/oil or hydraulic fluid applications
Filtration rating: ~15 micron absolute
Flow direction: outside-in
Pleated stainless steel or high-efficiency media
Reusable or replaceable depending on maintenance spec
High dirt-holding capacity
Stable flow under aircraft system pressures
Installed in dedicated aircraft filter housings
Used in rotorcraft fluid system protection