TV-45K

Autonomous operation of the TV-45K

The main advantage of the TV-45K is its autonomous mechanical operation. The measuring part does not need aircraft electrical power, signal wiring or electronic processing. Temperature is indicated directly at the place where the instrument is installed. This makes the thermometer useful as a simple cabin reference instrument, especially in aircraft where reliability and easy reading are more important than remote data transmission. Electrical connection, if present, is normally related only to scale lighting and not to the measurement itself.

Bimetallic measuring element inside the TV-45K

The TV-45K works with a bimetallic spiral. When cabin air temperature changes, the spiral twists or untwists and mechanically moves the pointer over the scale. This principle is simple, stable and suitable for aircraft cabin use. There are no pressure lines, sensors or amplifier units involved. Because the indication is mechanical, the instrument must be installed where cabin air can reach it normally. A poor installation point, blocked airflow or heat from nearby equipment can affect the indicated temperature.

Cabin temperature indication on helicopters

On Mi-8 / Mi-17-family helicopters and other rotorcraft, the TV-45K can be used for monitoring temperature in the crew cabin or passenger / cargo compartment. The instrument helps the crew or maintenance personnel check the general cabin environment without relying on complex environmental control system indications. It is especially practical in helicopter cabins where vibration, temperature changes and variable heating conditions are normal. The thermometer gives a direct local reading and can be used as a quick reference during operation or inspection.

TV-45K scale and lighting execution

The TV-45K scale is graduated in degrees Celsius and covers a wide aircraft cabin temperature range. The “K” execution is associated with cockpit lighting adaptation, usually for red or white illumination depending on the specific series and aircraft installation. The lighting circuit may use a low-voltage or aircraft DC supply, but this does not affect the basic temperature measurement. When ordering, the exact execution should be checked, because similar thermometers may differ by lighting type, scale marking, mounting details or documentation.

Inspection and maintenance of TV-45K

During inspection, the TV-45K is normally checked for pointer movement, scale readability, glass condition, mounting security and lighting operation if fitted. Since the measuring element is mechanical, the pointer should move smoothly and should not stick. The instrument should also be free from visible damage, moisture traces or deformation. For aviation supply, it is useful to confirm the designation, condition, passport or label, lighting voltage and compatibility with the aircraft panel or cabin installation point.