A-034-4-11

1000-meter range of the A-034-4-11

The A-034-4-11 belongs to the unified A-034-4 indicator family. Instruments in this family are generally similar in construction and operating logic, but differ by scale, measurement range and system configuration. This version displays altitude from 0 to 1000 meters, which makes it suitable for aircraft requiring radio-altitude indication beyond the narrow low-altitude range. Compared with 300 m or 700 m variants, the A-034-4-11 gives the crew a wider indication window while keeping the same familiar pointer-type cockpit format.

Scale graduation on the A-034-4-11

The A-034-4-11 scale is divided into three zones. From 0 to 20 meters, the division is 5 meters. From 20 to 100 meters, the division changes to 10 meters. From 100 to 1000 meters, the scale uses 100-meter divisions. This layout keeps the lower part of the scale more detailed, where smaller height changes matter most. At higher values, the scale becomes less dense and easier to read quickly. This is a practical layout for a radio-altimeter indicator with an extended 1000-meter display range.

Danger altitude warning on A-034-4-11

The indicator includes a Danger Altitude setting sector and a warning lamp integrated with the setting knob. The crew can set the required warning threshold according to the flight task or aircraft procedure. When the aircraft descends to the selected value, the warning circuit activates and provides a visual alert. This helps the pilot notice hazardous descent without constantly comparing the pointer position with the scale. The function is useful during approach, low-level flight, descent, operation over water, night flying or poor-visibility conditions.

Drop-out blinker and failure indication

The A-034-4-11 has a drop-out blinker flag that appears when the radio altimeter detects a fault or loses usable reflection from the ground surface. This is important because the pointer reading should not be trusted if the system is not receiving valid altitude information. The blinker gives the crew a direct visual indication that the radio-altimeter channel is unreliable or inoperative. During maintenance, this condition should be checked at system level, including the indicator, transceiver, antennas, cabling, connectors, power supply and protection circuits.

TEST function of the A-034-4-11

A front-panel TEST push button allows the crew or maintenance personnel to verify the indication channel. When the A-037 system is functioning correctly, pressing TEST moves the pointer to the control value. If the pointer does not move as expected, the blinker flag appears. This check helps confirm whether the cockpit indicator and the connected radio-altimeter circuit respond correctly. A failed TEST response should not automatically be treated as an indicator defect only, because the problem may also be in the A-037 electronics, wiring, antenna path or power circuits.

Compatibility and supply of A-034-4-11

The A-034-4-11 is installed on the cockpit instrument panel and works with A-037-1 series transceivers and associated antennas. Compatible versions may include A-037-1A, A-037-1B, A-037-1V and A-037-1G, depending on aircraft configuration and documentation. For supply or replacement, the full designation A-034-4-11 should be used. Similar A-034-4 indicators may look alike but differ by range, scale, warning layout, markings and compatibility. Before installation, the unit should be checked for documentation, service status, pointer movement, TEST response, blinker operation and connector condition.

Related instruments: A-034-4-8, A-034-4-8AF, A-034-4-3. These links are grouped by function and system context and do not indicate interchangeability.