A-034-4-22

Altitude display on the A-034-4-22 scale

The A-034-4-22 has a display range from 0 to 700 meters. The scale is divided unevenly, with finer resolution at low altitude and wider spacing at higher altitude. This makes the instrument easier to use in the area where radio altitude is most critical. From 0 to 20 meters, the scale uses 2-meter steps. From 20 to 50 meters, it changes to 5-meter steps. From 50 to 100 meters, the scale uses 10-meter steps, and above 100 meters the division increases to 50-meter steps. The layout is practical for cockpit reading, not just mathematically uniform.

Danger altitude warning on A-034-4-22

The indicator includes a combined rotary knob and warning lamp for setting a minimum safe altitude. The crew selects the desired danger altitude directly on the instrument. When the aircraft descends to the selected value, the warning circuit activates a visual signal. In this version, the warning is shown by a yellow triangle indicator. This function helps the crew notice a hazardous descent without continuously comparing the pointer position with the scale. It is a simple but important safety feature in low-level flight and approach conditions.

TEST mode and fault indication of A-034-4-22

The A-034-4-22 has a TEST function for checking the radio altimeter indication channel. When the TEST button is pressed and the system is serviceable, the pointer should move to the 15-meter reference indication. This confirms that the indicator and the connected system respond correctly. If the pointer does not move as expected, or if the radio altimeter system is not operating properly, a dropout flag appears across the display. This blenker gives the crew and maintenance personnel a clear warning that the indication should not be relied on until the system is checked.

A-034-4-22 with A-037 Variant 10 equipment

The A-034-4-22 works in the A-037 Variant 10 configuration. In this set, the indicator operates together with the A-037-1V transceiver, two A-037-2 antennas, wiring assemblies and mounting components. The radio altimeter measures height by using radio signals reflected from the surface below the aircraft. The indicator does not perform the measurement itself; it displays the result and provides warning and test functions in the cockpit. Because of that, troubleshooting should always include the full A-037 set, not only the front instrument.

Service and replacement notes for A-034-4-22

The A-034-4-22 should be checked for pointer movement, scale readability, TEST response, warning lamp operation, dropout flag condition, connector integrity and secure panel mounting. If the indicator is removed from storage or supplied as a spare, its condition and documents matter just as much as the external appearance. A similar A-034 indicator may have a different range, scale layout, system variant or compatible transceiver. For that reason, replacement should be made by full designation and confirmed against the A-037 Variant 10 documentation.

Identification and supply of A-034-4-22

For procurement, the full designation A-034-4-22 should be stated. Alternative descriptions such as A034-4-22 height indicator, A-034-4-22 pointer indicator or radio altimeter indicator may help clarify the item, but the exact part number remains the key identifier. It is also useful to specify that the instrument is required for the A-037 Variant 10 set with A-037-1V transceiver and A-037-2 antennas. Before installation, the unit should be checked for documentation, testability, storage condition, service history and compatibility with the target aircraft system.

Related instruments: A-037 Version 10, A-034-4-12, A-034-4-24. These links are grouped by function and system context and do not indicate interchangeability.