979494-4 — One-inch Diameter Pneumatic Shutoff Valve Repair & Overhaul

Component Overview

A one-inch diameter pneumatic shutoff valve is a small-line isolation valve that opens or closes a pneumatic air path on command, commonly a butterfly or poppet valve actuated by pneumatic pressure with solenoid pilot control. Sized for a one-inch duct, it serves lower-flow branches of the air management system such as instrument, service, or secondary bleed-air supplies, providing positive on-off control without pressure regulation. Within the system its role is straightforward flow isolation. Repair and overhaul are driven by seat and seal wear causing internal leakage, butterfly or poppet erosion, actuator diaphragm and spring fatigue, solenoid coil degradation, bearing or bushing wear, and contamination-induced sticking, all of which can prevent full opening or leak-tight closure and impair reliable valve operation.

Aircraft Application

Part number 979494-4 (One-inch Diameter Pneumatic Shutoff Valve) is installed on the Mitsubishi MU-300. QTC supports operators and MROs servicing this platform with certified repair and overhaul.

Our Repair Capability

QTC repairs and overhauls 979494-4 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 one-inch diameter pneumatic shutoff valve part numbers we repair — view all One-inch Diameter Pneumatic Shutoff Valve parts →

Frequently Asked Questions