A-034-4-17AN

Export version of the A-034-4-17 indicator

The A-034-4-17AN is technically equivalent to the A-034-4-17 indicator in design, operating principle and main performance characteristics. The key difference is the export execution. The A-034-4-17AN has an English-language dial and markings, which makes it suitable for export aircraft configurations and international operators. This detail matters in real supply work, because two instruments may be functionally the same but differ by dial language, cockpit standard, aircraft documentation and acceptance requirements. For replacement, the AN version should be requested when English cockpit markings are required.

A-034-4-17AN altitude scale and low-height readability

The A-034-4-17AN uses a 0–300 m scale with variable division spacing. The lower part of the scale is more detailed, because low-altitude flight requires better visual resolution. From 0 to 20 m, the scale division is 1 m. From 20 to 50 m, it changes to 2 m. From 50 to 300 m, the scale uses 10 m divisions. This layout lets the pilot read small changes near the ground without making the entire scale too crowded. It is a practical cockpit instrument rather than a simple linear gauge.

TEST function and control sector on A-034-4-17AN

The indicator scale includes a control sector from 13.3 to 16.5 m. This sector is used during functional checking of the radio altimeter indication channel. When the TEST button is pressed, the pointer should move to the reference value of 15 ±1.5 m if the system is operating correctly. This gives a quick check of the indicator response and related signal path. If the pointer does not enter the control sector or behaves irregularly, the A-037 system should be checked through the applicable maintenance procedure.

A-034-4-17AN in the A-037 radio altimeter system

The A-034-4-17AN works as part of the A-037 radio altimeter set. The full system includes the radio-altimeter equipment, transmitter-receiver section, antennas, power supply circuits, protection elements, wiring and cockpit indication. The system operates in the radio frequency range used for low-altitude measurement and provides continuous height information within its specified limits. The indicator is only the cockpit display element of this chain. If indication becomes incorrect, the cause may be in the indicator, transmitter-receiver unit, antennas, cable lines, power supply or protection circuits.

Cockpit installation and service of A-034-4-17AN

The A-034-4-17AN is intended for installation on the left instrument panel of the flight crew cockpit, according to the provided installation data. During maintenance, the instrument should be checked for pointer movement, scale readability, TEST response, connector condition, secure mounting and absence of mechanical damage. Since this is the English-dial export version, the dial marking should also be verified during acceptance. Similar A-034 indicators may have different ranges, scale language or system variants, so interchangeability should not be assumed by appearance alone.

Supply and identification of A-034-4-17AN

When ordering, the full designation A-034-4-17AN should be used, not only A-034-4-17. The “AN” suffix is important because it identifies the English-language export version. It is also useful to specify the required range, system compatibility and condition: new, from storage, repaired, overhauled or serviceable with documents. Before installation, the indicator should be matched with the aircraft documentation and A-037 radio altimeter configuration. Passport, inspection records, repair documents or operational documentation should be requested when the unit is supplied for aircraft use.

Related instruments: A-034-4-17, A-034-4-8AF, A-037 Version 4. These links are grouped by function and system context and do not indicate interchangeability.