8A-5301-370-001

8A-5301-370-001 hydraulic accumulator in Mi-8 systems

The 8A-5301-370-001 is an aircraft hydraulic accumulator used on Mi-8 series helicopters. It is installed in onboard systems where the working fluid must keep a pressure reserve during operation. The accumulator does not create pressure by itself. It stores part of the hydraulic energy already available in the system and returns it when line pressure drops or fluctuates. In maintenance documentation, this unit is treated as a pressure support and compensation element of the helicopter hydraulic circuit.

Pressure stabilization function of 8A-5301-370-001

The main function of the 8A-5301-370-001 is to smooth pressure changes in the working fluid. Pumps, valves and actuators can create short pressure pulses or pressure drops in the line. The accumulator works as a buffer volume and helps the system maintain more stable pressure. This reduces load on hydraulic components and supports more predictable operation of connected units. In some documentation, similar accumulator assemblies may also be referenced in connection with fuel or oil system pressure compensation.

8A-5301-370-001 in the Mi-8 hydraulic system

On Mi-8 helicopters, the accumulator operates as part of a larger hydraulic system. It works together with pumps, pipelines, valves, filters, fittings, actuators and control elements. The accumulator does not control these components directly. Its role is to provide stored pressure volume, compensate short-term pressure changes and support reserve capacity in the circuit. Exact installation location and connection must be checked by Mi-8 maintenance documentation, because aircraft configuration may differ by modification and repair history.

Nitrogen charging and pressure reserve

The 8A-5301-370-001 is a charged hydraulic accumulator. The gas side is normally charged with nitrogen, and the charging pressure must be checked according to the aircraft documentation and applicable service procedure. Nitrogen quality and charging rules are important because incorrect gas pressure can make the accumulator ineffective or create abnormal system behavior. If pressure instability is reported, the accumulator should not be blamed automatically. Pumps, leaks, valves, contamination and incorrect charging pressure should also be checked.

Identification of 8A-5301-370-001

The same accumulator can appear in documentation with different writing styles. In English export requests, it is usually written as 8A-5301-370-001. In Russian documentation, the designation may be written as 8А-5301-370-001, 8А-5301-370/1, 8А.5301.370-01 or 8А.5301.370.001. The marking on the cylinder may also appear as 8А.5301.370.01. These formats should be cross-checked with the aircraft parts catalog and product passport before confirming interchangeability.

Alternative variant 8A-5301-370-002

An alternative variant, 8A-5301-370-002, may be found in documentation. It should not be treated as automatically interchangeable without verification. Accumulators with similar dimensions or similar designation may have different pressure settings, connection details, internal construction or system application. For procurement, the correct part number should be taken from the aircraft catalog, installed unit marking, passport and maintenance documentation.

Installation and system checks

Before replacement, the installed accumulator should be checked by designation, system location, operating pressure, volume and connection type. The hydraulic system should be depressurized and serviced only according to the approved maintenance procedure. After installation, the system should be checked for leaks, correct pressure behavior and proper operation of connected hydraulic equipment. If the accumulator is supplied from storage or after repair, condition of the cylinder body, threads, fittings, charging port and documentation should be reviewed before installation.

Supply and documentation for 8A-5301-370-001

For procurement, the unit should be specified by the full designation 8A-5301-370-001, with Russian marking variants noted where necessary. The product may be supplied new, from storage, repaired, overhauled or serviceable depending on availability. For aviation use, product passport, acceptance documents, test report or overhaul documentation should be confirmed before delivery. Passport name may be listed as hydraulic accumulator 8А-5301-370/1, while the cylinder marking may use the format 8А.5301.370.01.

Product Type: Aircraft hydraulic accumulator
Designation: 8A-5301-370-001
Russian Designation: 8А-5301-370-001
Passport Name: Hydraulic accumulator 8А-5301-370/1
Cylinder Marking: 8А.5301.370.01
Code / Drawing Reference: 8А.5301.370-01; also referenced as 8А.5301.370.001
Alternative Variant: 8A-5301-370-002, subject to catalog verification
Function: Pressure storage, pressure reserve and stabilization of working fluid
Application / Where Used: Mi-8 helicopter hydraulic systems; related aircraft fluid systems where applicable by documentation
System / Installation Area: Hydraulic system
Compatible Aircraft / Equipment: Mi-8 helicopter family depending on modification and installed system configuration
Accumulator Capacity: 2.5 L
Working Pressure: 65 kgf/cm²
Minimum Pressure Reference: Not less than 28 kgf/cm², if specified for the applicable system condition
Gas Charging: Nitrogen charging according to aircraft documentation; nitrogen per applicable standard reference such as GOST 9239-59 where specified
Weight: Approx. 4.5 kg
Working Medium: Aircraft hydraulic fluid according to Mi-8 system documentation
Interchangeability / Replaceability: Must be confirmed by aircraft parts catalog and installed-unit marking
Condition: New / from storage / repaired / overhauled / serviceable depending on availability
Inspection / Testing: Cylinder inspection, marking check, leak check, pressure check, nitrogen charge check, fitting and thread inspection
Technical Documentation: Product passport, Mi-8 maintenance documentation, spare parts catalog, test / acceptance documents as applicable

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