GA 111

How the GA 111 unit operates

Control pressure opens the internal passage to the cylinder. When the control command is removed, the lock retains the working medium in the isolated chamber and helps hold the connected actuator in position. The built-in thermal relief valve performs a separate protective task by relieving a trapped volume if thermal expansion increases pressure. This function does not make the unit a directional distributor or a continuous pressure regulator. Reliable operation depends on a clean working medium, serviceable seating surfaces and seals, undamaged threads and correct body orientation. If a connected actuator does not hold position or line pressure falls, maintenance personnel normally inspect not only GA 111, but also the pump, filter, pipelines, fittings, power cylinder and adjacent valves in the same circuit.

Published operating data and connections

Published catalogue data gives a nominal pressure of 21 MPa / 210 kgf/cm², a nominal flow capacity of 15 L/min, hydraulic resistance of not more than 0.3 MPa / 3 kgf/cm² at nominal flow, an operating temperature range of −60 °C to +60 °C, and the following opening parameter: thermal relief valve opens at 26 MPa / 260 kgf/cm². Mass: not more than 0.31 kg. Connections: D1 M12×1; D2 M10×1; D3 M12×1. These values help distinguish the unit from similar catalogue positions and verify the mounting location. Published technical data is consistent with the hydraulic-lock function described in aircraft maintenance documentation. Before installation, the figures should be checked against the product passport, current technical specification and documentation for the particular aircraft. If the supplied unit or its passport records a different execution, the documentation accompanying that unit takes precedence.

Installing GA 111 and confirming aircraft applicability

Installation area: Power-cylinder pressure and control lines. The GA 111 designation is documented in the hydraulic systems of the Il-76, Mi-171Sh / Mi-8 family and Mi-26. The exact installation position still depends on the aircraft modification and system diagram. This confirms use of the designation, but it does not make different family executions interchangeable. Routine maintenance normally includes checking the marking, flow direction, connection tightness, body condition and contamination. Selection by diameter or photograph alone is unsafe because a similar body may be produced for another medium, thread, flow capacity or setting. Pumps, cylinders and distributors connected in the same circuit are associated components, but they perform different tasks and must not be presented as interchangeable with this unit. Before installation, the unit should be examined for corrosion, damaged threads and evidence of unsuitable storage; after connection, the approved leakage and functional checks should be completed. Test pressure, preservation method and depreservation procedure cannot be assigned from a general family description and must come from the passport or approved repair documentation. If the nameplate and accompanying documents disagree, installation should stop until the execution is clarified.

Designations, documents and related products

The primary English catalogue designation is GA 111. Procurement lists, export records and Cyrillic documentation may also use: GA-111; GA111; ГА 111; ГА-111; ГА111. These forms are included to identify one product, not to create separate items. An enquiry should state the complete marking, system type, working medium, mounting position, required condition, delivery set and whether a passport or test record is needed. The control valves and hydraulic units category also contains related positions: GA 111A, GA 111N, OK 10A, OK 18A. They belong to the same commercial and functional group, but an internal link does not establish compatibility or interchangeability. The final selection must follow the illustrated parts catalogue and approved aircraft documentation. Serial number, production date and actual delivery set are confirmed separately for the specific supplied unit.