321935 — Pressure Actuated Butterfly Valve Repair & Overhaul

Component Overview

The pressure actuated butterfly valve is a butterfly-type flow control valve whose disc is positioned by air pressure rather than by an electric drive, using upstream or controlled pressure acting on a piston or diaphragm actuator to open, close, or modulate the disc. Used in pneumatic and air management ducting, it regulates or isolates airflow using the working medium itself, often with a pilot or sensing arrangement that sets the actuating pressure. Because actuation depends on clean, properly scheduled pressure, common faults include diaphragm or piston seal leakage, contamination and blockage of pilot and sensing passages, disc and seat seal wear causing leakage, shaft and bearing wear, spring fatigue, and corrosion. Functional response, leakage, and calibration testing direct seal replacement and actuator overhaul.

Aircraft Application

Part number 321935 (Pressure Actuated Butterfly Valve) is installed on the Saab 340. QTC supports operators and MROs servicing this platform with certified repair and overhaul.

Our Repair Capability

QTC repairs and overhauls 321935 to the original manufacturer's specifications under our FAA and EASA Part 145 approvals. Our team — including former OEM pneumatic & air management engineers — performs teardown, inspection, cleaning, component replacement, functional testing, and certification, returning a serviceable unit with the appropriate airworthiness release. We also develop repairs for rejected and beyond-economic-repair (BER) hardware.

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Related Parts

Other pressure actuated butterfly valve part numbers we repair — view all Pressure Actuated Butterfly Valve parts →

Frequently Asked Questions