Shutoff Valves Repair & Overhaul

A shutoff valve provides positive isolation of an air duct within the aircraft pneumatic and air-management system, opening or closing a bleed or conditioned-air line on command. Used wherever a supply must be cleanly started, stopped, or isolated, these valves protect downstream equipment and allow sections of the pneumatic network to be shut off for control or fault response. Many designs combine isolation with flow control, such as flow control and shutoff valves and bi-level flow control and shutoff valves that establish defined flow schedules in addition to closing fully.

Construction varies with the application. Butterfly shutoff valves rotate a disc element a quarter turn to seal against or clear the bore, and are driven pneumatically, electrically, or by solenoid logic. Smaller lines use pneumatic or electric shutoff valves and solenoid valves, including three-way and high-pressure variants. QTC repairs and overhauls shutoff valves from platforms including Gulfstream, Bombardier, Dornier, Hawker Beechcraft, Lockheed, and Pilatus.

Because shutoff valves cycle repeatedly while carrying hot, high-pressure air, overhaul is driven by butterfly or poppet and seat wear and leakage from cyclic seating, actuator, motor, or solenoid failure, gear-train and bearing wear causing binding or slow travel, position-switch and limit malfunction, contamination-induced sticking, and shaft seal and bushing degradation that leads to failure to open or close fully.

QTC overhauls shutoff valves under its FAA and EASA Part 145 approvals. Each valve is inspected on receipt and fully disassembled to access the flow element, shaft, body, actuator, and control hardware. Worn seats and seals, bushings, bearings, and the butterfly or poppet element are replaced or restored, and the pneumatic, electric, or solenoid actuator section, including any gear train and position switches, is overhauled to specification.

The reassembled valve is recalibrated where applicable and functionally tested, with leakage, flow, and open and close actuation checks confirming full seating and travel across the operating range. Solenoid and electric-actuator response, position-switch indication, and any limit settings are verified as part of the test sequence. Where a unit provides flow control or bi-level flow scheduling, those positions are confirmed as well. Valves meeting requirements are returned to service with the appropriate certification, supported by QTC's engineering experience with pneumatic and air-management hardware.