BMP Series 2

BMP Series 2 transition unit in aircraft navigation circuits

The BMP Series 2 is an aircraft mechanical transition unit used in pilotage and navigation equipment where different types of angular transmission devices must work together in one measuring circuit. Its main task is to match a contactless sine-cosine transformer with a receiving selsyn circuit. In practical aircraft systems, this kind of unit is needed when the angle source and the cockpit indicator use different electrical conversion principles. The BMP does not create navigation data by itself; it transfers and adapts angular information so that the receiving instrument can display it correctly.

BMP Series 2 for radio compass angle transmission

One of the typical functions of the BMP Series 2 is transmission of radio bearing or course-angle information from an automatic direction finder system to cockpit pointer indicators. The block is used where the heading or bearing signal is formed by a sine-cosine transformer, while the receiving indicator works through a selsyn with stator windings connected in a star circuit. Without this matching unit, the signal format from the transmitter may not be suitable for the receiving device. The BMP therefore acts as a necessary link between the navigation sensor and the cockpit display chain.

BMP-01 / BMP-02 Series 2 in Mi-8 and Mi-171 equipment

On Mi-8 / Mi-17 family helicopters, including Mi-8T, Mi-8MTV, Mi-171 and Mi-171E versions, the BMP Series 2 may be used in navigation and radio-compass indication circuits. These helicopters rely on several electromechanical and electrical signal transmission devices, especially in older or mixed-generation avionics layouts. The BMP helps keep compatibility between the automatic radio compass equipment and cockpit indication devices. Its exact installation depends on the avionics set, aircraft modification, and the equipment list approved for the specific helicopter.

Aircraft systems using the BMP Series 2

The BMP Series 2 can also be found on Mi-26 / Mi-26T helicopters and Il-76 / Il-76TD aircraft, depending on configuration. In these systems, the block may be linked with automatic flight control equipment, measuring circuits, or automatic direction finder systems such as ARK-11, ARK-15M, ARK-15 or ARK-UD. On some aircraft it may work in circuits associated with SAU-1T-2B or SAU-155MP systems. Because the block is part of a larger signal chain, applicability must always be checked by the exact aircraft modification and installed avionics configuration.

Operating principle of the BMP transition block

The BMP Series 2 is used when angular information has to be mechanically and electrically adapted between transmitter and receiver elements. The source side may use a contactless sine-cosine transformer, while the receiving side is based on a selsyn system. The transition block makes the two parts of the measuring circuit compatible and allows the cockpit instrument to follow the transmitted angular position. This is especially important in navigation systems where a wrong bearing indication or unstable signal transfer can mislead the crew and make the instrument unreliable.

Installation and service conditions of BMP Series 2

The BMP Series 2 is designed for aircraft operating conditions, including vibration, temperature changes, pressure variation and long service periods in technical compartments. The unit is normally installed as part of onboard navigation or automatic control equipment rather than as a cockpit control element. During inspection, attention should be paid to the housing, connector condition, mounting points, signs of corrosion, wiring, and stability of signal transmission in the connected circuit. Since this is a matching block, a fault may appear as an indicator error rather than as an obvious failure of the unit itself.

Identification and supply of BMP Series 2

For procurement, the unit should be specified by full designation and series: BMP Series 2, BMP-01 Series 2, BMP-02 Series 2, or by the drawing number where available. Similar-looking units may differ by circuit execution, connector layout, installation details, or aircraft applicability. Before ordering, it is better to confirm the aircraft type, modification, associated radio compass or automatic control system, and required documentation. For aviation supply, the block may be offered new, from storage, repaired, or overhauled depending on availability and passport status.

Product Type: Aircraft mechanical transition block / navigation signal matching unit
Designation: BMP Series 2
Alternative Designations: BMP-01 Series 2; BMP-02 Series 2
Function: Matching of sine-cosine transformer signals with selsyn-based receiving circuits
Application / Where Used: Aircraft pilotage, navigation and measuring systems
System / Installation Area: Navigation equipment, radio compass indication circuits, automatic control and measuring circuits depending on aircraft configuration
Primary System Function: Transmission and adaptation of radio bearing / course-angle information to cockpit indicators
Signal Source Type: Contactless sine-cosine transformer
Receiving Device Type: Selsyn receiver with stator windings connected in star configuration
Associated Systems: ARK-11, ARK-15M, ARK-15, ARK-UD, SAU-1T-2B, SAU-155MP depending on aircraft configuration
Compatible Aircraft / Equipment: Mi-8, Mi-8T, Mi-8MTV, Mi-17, Mi-171, Mi-171E, Mi-26, Mi-26T, Il-76, Il-76TD depending on installed avionics
DC Supply Voltage: 27 ±2.7 V
DC Current Consumption: Not more than 0.12 A
AC Supply Voltage: 32.4–37.8 V
AC Current Consumption: Not more than 0.6 A
Supply Frequency: 400 ±8 Hz
Dimensions: 270 × 93 × 84 mm
Weight: 1.5 kg
Drawing / Decimal Number: 6S2.399.021 / 9Ya2.399.001
Operating Conditions: Aircraft vibration, temperature and pressure conditions according to applicable technical documentation
Technical Documentation: Product passport, acceptance documents and aircraft avionics documentation as applicable

All shipments are carried out from our international warehouse in Dubai (UAE), as well as from our partners’ remote warehouses.

In Stock — items available in stock at the Dubai warehouse are dispatched within 5–10 business days after receiving 100% prepayment.

Remote Stock — items available at our partners’ remote warehouses are supplied within an average of 30–45 business days after receiving 100% prepayment.

Pre-Order — made-to-order products are manufactured and delivered within an average of 45–60 business days. Payment terms: 50% advance payment to start production, with the remaining 50% paid before dispatch from the Dubai warehouse after full readiness for shipment.

Returns & Changes (Restocking Fee)
For selected items, a RESTOCKING FEE of 10% may apply in case of return, order cancellation, or changes to the order specifications. This condition applies only to certain products and is confirmed at the order approval stage.

Warranty
All products are covered by a standard 6-month warranty.
Extended warranty is available upon request and is agreed individually; it may affect the final product price.