8A-5103-220

Four mechanical control channels

The unit combines four pilot-control paths in one installation: longitudinal cyclic control, lateral cyclic control, directional pedal control and collective-pitch control. These paths correspond to the helicopter pitch, roll, yaw and main-rotor collective functions. Movement introduced by the pilot is transmitted through rods, shafts and bellcranks, then passed toward the downstream control linkage and boost-control installation.

Documented parts within or immediately associated with the assembly include the 8A-5103-222 longitudinal-control shaft, 8A-5103-100 lateral-control shaft, 8A-5103-223 pedal-control shaft and 8A-5103-225 collective-control shaft. The assembly also contains supports, bearings, seals and multiple bellcranks that preserve the required geometry of each mechanical path. These parts explain the elongated structure visible in the product photograph and show why the complete assembly must be inspected as a coordinated mechanism rather than as an isolated lever.

Connection with the Mi-8 control linkage

In the Mi-8 installation, the 8A-5103-220 works with the cockpit controls and the mechanical rods that carry pilot inputs. The installation documentation identifies the 8A-5102-80 longitudinal-control rod and 8A-5102-55 lateral-control rod in the immediate linkage. The wider control system also includes the manual control column 8AT-5101-00-3 or -5, the RU-2 cyclic grip, the collective-control lever and the helicopter pedal mechanism. The exact connected rod and lever configuration depends on the airframe modification.

The unit must be aligned so that movement is transmitted without binding, unintended contact or incorrect angular travel. Fasteners, splined shaft connections, bearing supports, bellcranks and control-rod attachments are all relevant to installation quality. Approved rigging procedures and specified tightening values must be followed during installation; visual similarity alone is not enough to establish suitability.

Interface with hydraulic boost components

Although 8A-5103-220 is primarily a mechanical control assembly, it operates within the same flight-control chain as the helicopter hydraulic boost equipment. The broader system includes the 8A-5104-200 or 8AMT-5104-200 booster installation and hydraulic control units such as KAU-30B and RA-60B. The 8AT-5103-550 hydraulic-stop cylinder is another associated component listed in the Mi-8 flight-control system.

This relationship does not mean that the control unit itself is a hydraulic actuator. Its role is to organise and transmit mechanical control movement through the four channels. Hydraulic boosters then provide the force assistance required by the rotor-control system. Troubleshooting must therefore consider the complete path from cockpit controls through the mechanical linkage, hydraulic boost components and final rotor-control mechanisms.

Identification and sourcing requirements

Before ordering, compare the complete designation, mounting base, shaft arrangement, bellcrank positions and attachment points with the removed assembly and approved helicopter documentation. Confirm the aircraft model, modification, quantity and required documentation. Related 171A-5103-220 and 184-5103-220 assemblies may perform a similar system function but remain separate part numbers until approved interchangeability is established.

8A-5103-220 is currently listed as out of stock. Aviamisto can review sourcing options when a confirmed requirement is received. Send the exact part number, helicopter modification, quantity, delivery destination and documentation requirements. Availability, condition, year of manufacture, photographs, passport and delivery terms will be confirmed for the specific unit offered.