UI3-9

Three-pointer aircraft indicator UI3-9

UI3-9 is an electrical three-pointer aircraft indicator used for simultaneous cockpit monitoring of oil pressure, fuel pressure and oil temperature. The instrument belongs to the unified UI3 family and is installed on the instrument panel where the crew can read several engine parameters from one compact unit. It is an indicating instrument only. It does not measure pressure or temperature by itself and does not include a computing or control block. All measured values come from external pressure transmitters and temperature receivers installed on the engine, fuel system or oil system.

Oil and fuel pressure indication through UI3-9

Two channels of the UI3-9 work as pressure indicators. The oil pressure channel is used with an inductive pressure transmitter matched to the oil pressure range. The fuel pressure channel works with a higher-range pressure transmitter installed in the fuel system. In both cases, the indicator receives an electrical signal from the remote transmitter and moves the corresponding pointer on the scale. If the reading is unstable or absent, the fault may be in the indicator, transmitter, connector, wiring, AC supply or grounding. The full measuring circuit should be checked before replacing the instrument.

UI3-9 oil temperature channel and related receivers

The third channel of the UI3-9 is used for oil temperature indication. This channel works with resistance-type temperature receivers such as P-1 or P-63, depending on the aircraft documentation. The temperature circuit is normally powered from the aircraft DC network and operates separately from the pressure channels. In service, oil temperature indication is used together with pressure readings to assess engine operating condition, lubrication performance and possible abnormal heating. A wrong temperature reading can come from the receiver, bridge circuit, wiring, connector or the indicator itself.

Aircraft and equipment application of UI3-9

UI3-9 is used on aircraft and some special ground equipment of Soviet and Russian design. Typical aircraft applications include Yak-18T, Yak-52, An-2 in some modifications and repair configurations, Mi-2, Mi-8 and Ka-26. The indicator may also be found on special vehicles, airfield power units and diesel generator sets using converted aviation or heavy-duty engines. Installation depends on the panel layout, engine type, sensor set and repair history. A visually similar UI3-series instrument is not automatically interchangeable if the scale ranges or connected transmitters differ.

Connected sensors and power circuits around UI3-9

The UI3-9 normally works with ID, IDT or IMD series inductive pressure transmitters. For the oil pressure channel, the transmitter is selected for the lower pressure range. For the fuel pressure channel, the transmitter is selected for the higher fuel pressure range. The oil temperature channel is connected to a P-1 or P-63 temperature receiver. The pressure channels require aircraft AC supply, often from onboard converters or step-down transformers, while the temperature circuit uses DC power. This mixed supply arrangement is why wiring diagrams matter during installation and troubleshooting.

Identification and ordering of UI3-9

Before ordering UI3-9, the marking on the instrument should be compared with the aircraft parts catalog, cockpit panel layout and wiring diagram. The main points to confirm are scale ranges, connected transmitter types, temperature receiver type and power supply arrangement. If the instrument is being selected for an aircraft after overhaul or for special ground equipment, a photo of the installed unit and the sensor list is useful. The product is also known under alternative designations UI3-9, UI-3-9 and УИ3-9.

Product Type: Electrical three-pointer aircraft indicator
Designation: UI3-9
Alternative Designations: UI-3-9, УИ3-9, УИ-3-9
Function: Indication of oil pressure, fuel pressure and oil temperature
Application / Where Used: Aircraft engine monitoring systems and some special ground equipment
System / Installation Area: Cockpit instrument panel / engine monitoring panel
Compatible Aircraft / Equipment: Yak-18T, Yak-52, An-2 in some configurations, Mi-2, Mi-8, Ka-26, special vehicles, airfield power units and diesel generator sets with compatible sensor systems
Associated Equipment: ID, IDT, IMD pressure transmitters; P-1, P-63 temperature receivers
Oil Pressure Measurement Range: 0…0.8 MPa
Oil Pressure Working Range: 0.15…0.65 MPa
Fuel Pressure Measurement Range: 0…10 MPa
Fuel Pressure Working Range: 1.5…8.5 MPa
Oil Temperature Measurement Range: −60…+260 °C
Oil Temperature Working Range: −40…+240 °C
Pressure Transmitter Compatibility, Oil Channel: ID-0.8, IDT-0.8, IMD-0.8 or equivalent according to aircraft documentation
Pressure Transmitter Compatibility, Fuel Channel: ID-10, IDT-10, IMD-10 or equivalent according to aircraft documentation
Temperature Receiver Compatibility: P-1, P-63
AC Power Supply for Pressure Channels: 36 V, 400 Hz
DC Power Supply for Temperature Channel: 27 V DC
Technical Documentation: Aircraft maintenance manual, wiring diagram, parts catalog, manufacturer technical documentation

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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.