AP-34B Series 2
autopilot
Description
AP-34B Series 2 autopilot on Mi-8 and Mi-17 helicopters
The AP-34B Series 2 is a four-channel electro-hydraulic automatic flight control system used on Mi-8 and Mi-17 helicopter variants. It is installed to reduce pilot workload and keep the helicopter stable in the main flight regimes. The system works with pitch, roll, heading, altitude and airspeed control logic, using aircraft motion data and sending corrective signals to the helicopter control system. It does not replace the pilot. The crew keeps full control of the helicopter and can override the autopilot at any moment.
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Stabilization work of the AP-34B Series 2
In flight, the AP-34B Series 2 works as a closed-loop stabilization system. It reads signals from rate sensors, compensation devices and associated onboard equipment, then forms corrective commands for the hydraulic actuators. These commands damp unwanted movement and help hold the selected attitude or flight parameter. The system is active in hover, climb, descent, transitions and level flight. Its value is especially clear in long flights, low-visibility conditions and regimes where the crew must keep the helicopter stable while monitoring navigation, engine parameters and external conditions.
Four control channels of the AP-34B system
The AP-34B Series 2 is built around four main control channels. Pitch and roll channels stabilize helicopter attitude. The yaw channel is used for heading stabilization and damping of rotation around the vertical axis. The altitude channel helps maintain the selected height, while airspeed stabilization is provided through the pitch channel. This structure gives the pilot a more stable aircraft without taking away manual control. The system helps smooth corrections, reduce oscillations and keep the helicopter within the selected flight mode.
AP-34B Series 2 equipment set
A complete AP-34B Series 2 set includes several separate units rather than one single block. The system uses a control panel, control unit, compensation sensor, rate sensors for roll, pitch and yaw, a navigation-pilot amplifier block, a zero indicator and an altitude corrector. These modules work together inside the same control loop. If one component is missing or has the wrong modification, the system may not operate correctly. For supply, repair or replacement, it is important to specify whether the request is for the complete AP-34B set or for one separate module.
Pilot interaction with the AP-34B Series 2
The AP-34B Series 2 is designed to assist the pilot, not to take independent control of the helicopter. The pilot can fly manually with the system engaged or disengaged, depending on the flight task and operating procedure. Control authority of the actuators is mechanically limited, so the autopilot can only apply restricted corrections. This limitation is important for safety: the system can stabilize and damp movements, but it cannot move the controls through their full travel. The pilot remains the final control authority in all flight modes.
System integration on Mi-8 family helicopters
The AP-34B Series 2 is used on Mi-8T, Mi-8MT, Mi-8AMT, Mi-8MTV-1, Mi-17 and related variants, depending on the installed avionics and flight-control configuration. It interfaces with gyro sensors, altitude equipment, navigation-pilot amplifier circuits and hydraulic servo actuators. Because helicopter versions may differ in wiring, block arrangement and equipment layout, compatibility must be checked by the aircraft documentation. When replacing modules, part numbers, series, connector type, power supply and system configuration should be verified before installation.
Supply and documentation for AP-34B Series 2
For procurement, the AP-34B Series 2 should be described either as a complete automatic flight control system or as individual components with exact part numbers. This matters because the control panel, control unit, sensors and amplifier blocks are separate supply positions. A complete set should be checked for module composition, condition, passport documents and compatibility with the target helicopter. For aircraft use, factory passport, operation manuals, overhaul records, bench-test results and serviceability documentation are normally required or requested before installation.
Technical details
Technical Specifications: AP-34B
| Category | Details |
| Product Type | Automatic Flight Control System (AFCS) |
| Purpose | Automatic stabilization and flight control assistance |
| Systems | Four-channel electro-hydraulic autopilot |
| Channels | Pitch, roll, yaw (heading), altitude + airspeed through pitch |
| Application | Mi-8, Mi-8T, Mi-8MT, Mi-8AMT, Mi-8MTV-1, Mi-17 |
| Power Supply | 27 V ±10% DC / 36 V AC, 400 Hz |
| Ready Time | ≤ 2 minutes |
| Stabilization Accuracy | ±1° heading; ±0.5° pitch/roll; ±6 m altitude; ±10 km/h airspeed |
| Maximum Servo Authority | ~20% of total control travel |
| Operating Phases | Hover, climb, descent, level flight, transitions |
| Components Included | 6S2.390.007-3, 6S2.399.000, 6S2.553.002, DUS-1209G/E/K, BU-NPP-V, IN-4, KV-11 |
| Integration | Interfaces with gyro sensors, altitude devices, navigation-pilot amplifiers |
| Pilot Interaction | Manual flight allowed with AP engaged or disengaged |
| Functional Mode | Closed-loop stabilization with pilot override |
| Category | Avionics / Flight-control equipment |
| Documentation | Factory passport + operation manuals |
Payment & delivery
Orders ship from our hub in Dubai. Partner stock is first transferred to Dubai, then shipped to you.
Dubai stock: 100% before dispatch. Partner stock (Remote stock) and Pre-order: 50% advance payment to start the order and 50% before shipment from Dubai to you.
Availability, lead time, delivery cost and payment terms are confirmed for your order before payment.
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