BA-137-2S

BA-137-2S automatic control unit for anti-icing systems

BA-137-2S is an aircraft automatic control unit used in engine anti-icing systems. The unit processes signals from icing detectors and controls warning and heating circuits related to inlet guide vane icing detection. In the supplied context, BA-137-2S is associated with Il-76 aircraft and D-30KP / D-30KU engine installations, depending on configuration and documentation. The block belongs to aircraft electrical automation equipment and operates as part of the engine anti-icing and icing warning system.

Function of BA-137-2S in engine icing detection

The main function of BA-137-2S is to receive an icing signal from the engine icing detector and issue the required control commands. When the detector identifies icing conditions, the signal is transmitted to the automatic unit. The BA-137-2S then activates the corresponding cockpit warning indication and controls the heating circuit of the detector. This allows the crew and onboard system to detect ice formation in the engine inlet area and maintain detector operability during icing conditions.

Operation with DO-206 icing detector

BA-137-2S works together with DO-206 type icing detectors installed near the engine inlet guide vane area. In the source context, when the inlet openings of the DO-206 detector are blocked by ice, an internal contact closes and sends an electrical signal to the BA-137 unit. The control unit processes this signal and switches the related warning and heating circuits. After ice is removed and detector contacts open, the unit keeps the warning and heating circuits active for a short delay period before switching them off.

Warning and heater control logic

The BA-137-2S unit controls two main output functions: cockpit icing warning and detector heater supply. When an icing condition is detected, the unit issues power to the cockpit warning annunciator for inlet guide vane icing and also supplies power to the heating element of the DO-206 detector. The heating element helps cyclically clear the detector pin or sensing area from accumulated ice. According to the source context, after the detector contact opens, the unit switches off the heater and warning indication with a fixed delay.

Electrical and construction features of BA-137-2S

BA-137-2S operates from the standard aircraft 27 V DC network. The supplied context gives an operating voltage range of 18 to 30 V DC and self-consumption not exceeding 0.5 A, excluding switched heater load. The unit is housed in a metal protective casing with aviation-type plug connector for integration into the anti-icing system wiring. The block is described as vibration-resistant and suitable for aircraft operating conditions, including temperature variation, engine-related vibration and installation in heated or unheated aircraft compartments.

Identification and ordering of BA-137-2S

Before ordering BA-137-2S, the buyer should confirm the aircraft type, engine type, anti-icing system configuration, associated icing detector and required series. The unit may be required for engine anti-icing system repair, replacement of a defective automation block, stock replenishment or restoration of Il-76 / D-30KP equipment. It is important to confirm whether the request concerns BA-137-2S specifically or another BA-137 modification of the second or third series. Product passport, test records, wiring data and connector condition should be checked before shipment.

Product Type: Automatic control unit / engine anti-icing automation block
Designation: BA-137-2S
Russian Designation: БА-137-2С
Alternative Designations: BA-137, БА-137, BA-137 Series 2, БА-137 2-й серии, BA-137 Series 3, БА-137 3-й серии
Function: Processing of engine icing detector signals and control of warning / heater circuits
Application / Where Used: Aircraft engine anti-icing system
System / Installation Area: Engine inlet guide vane icing detection and anti-icing control circuits
Compatible Aircraft / Equipment: Il-76 aircraft according to source context and documentation
Associated Engines: D-30KP / D-30KU engines according to source context
Associated Icing Detector: DO-206 type icing detector
Associated Warning Indication: Cockpit warning annunciator for inlet guide vane icing
Nominal Supply Voltage: 27 V DC
Operating Voltage Range: 18 to 30 V DC
Self-Consumption Current: Not more than 0.5 A, excluding switched heater load
Switched Current Type: DC circuits for relays, warning indication and detector heating elements
Delay-Off Time: 5 ± 1 seconds
Input Signal Type: Discrete contact signal / 27 V DC control signal from engine icing detector, depending on wiring configuration
Output Circuits: +27 V supply to DO-206 detector heater and cockpit icing warning annunciator
Circuit Protection Context: Heater circuits typically protected by AZSGK-type circuit breakers according to source context
Operating Temperature Range: -60 °C to +60 °C according to source context
Housing: Metal protective casing with anti-corrosion coating
Connection Type: Quick-release aviation plug connector
Weight Reference: Approximately 1.2 to 1.5 kg depending on series and relay board modification
Form Factor: Monoblock unit with cassette or flange mounting, depending on execution
Category: Aircraft electrical automation equipment / anti-icing system component
Condition: New / As-Stored / Overhauled / Serviceable, depending on availability
Technical Documentation: Product passport, aircraft maintenance documentation, anti-icing system wiring diagram, test records and inspection documents if available

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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.