778695-1 — Pressure Regulating and Shutoff Valve Repair & Overhaul

Component Overview

A pressure regulating and shutoff valve manages engine bleed air by both throttling downstream pressure to a regulated setpoint and providing positive shutoff on command, controlling supply to air-conditioning packs, anti-ice, and pneumatic users. Within air management, it combines a butterfly or poppet flow element, a pneumatic actuator referenced to a sensing line, and a solenoid or torque motor for shutoff, balancing reference pressure against spring force to hold the regulated value. Exposed to high temperature, vibration, and contaminated bleed air, it degrades through butterfly and bearing wear, actuator diaphragm fatigue, solenoid coil and seal deterioration, spring relaxation, and carbon or soot fouling that causes regulation drift, sluggish response, leakage, or failure to close. Overhaul restores actuation, recalibrates the regulation band, and verifies leakage and shutoff.

Aircraft Application

Part number 778695-1 (Pressure Regulating and Shutoff Valve) is installed on the Bombardier Dash 8. QTC supports operators and MROs servicing this platform with certified repair and overhaul.

Our Repair Capability

QTC repairs and overhauls 778695-1 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 regulating and shutoff valve part numbers we repair — view all Pressure Regulating and Shutoff Valve parts →

Frequently Asked Questions