A-037-2

Transmit and receive role of the A-037-2

A typical A-037 installation uses two A-037-2 antennas. One antenna is used for transmitting the radio-frequency signal toward the surface below the aircraft, while the second antenna receives the reflected return signal. This separation helps the radio altimeter form a stable signal path between the aircraft and the underlying surface. The reflected signal is then sent to the transceiver, where the altitude measurement is processed and passed to the cockpit indicator and warning circuits.

A-037-2 with A-037-1 series transceivers

The A-037-2 antenna works with A-037-1 series transceivers, including A-037-1A, A-037-1V and A-037-1G, depending on the system variant and aircraft configuration. It is also used together with the corresponding A-034-4 series cockpit indicators. The antenna is only one element of the radio altimeter set, so compatibility should be confirmed by the installed A-037 version, transceiver type, indicator version, wiring layout and aircraft documentation.

Signal path in the A-037 system

In the A-037 radio altimeter system, the transceiver generates the microwave signal and sends it to the transmitting antenna. The A-037-2 antenna radiates the signal downward toward the surface. After reflection from terrain or water, the receiving antenna captures the return signal and routes it back to the transceiver. The transceiver then processes the received signal and forms altitude data for cockpit indication, low-height warning and fault monitoring. The antenna itself does not compute height and has no internal signal-processing function.

Installation of the A-037-2 antenna

The A-037-2 is mounted externally on the aircraft fuselage according to approved installation instructions. Correct orientation is important because the antenna must be directed toward the surface below the aircraft. Installation should also avoid obstruction by airframe structures, covers, equipment or incorrect mounting position. Since radio altimeter performance depends heavily on the antenna path, poor installation, damaged connectors, cable issues or incorrect positioning can affect altitude indication and warning reliability.

Inspection and service notes for A-037-2

During maintenance, the A-037-2 antenna should be checked for physical condition, secure mounting, connector integrity, surface damage, corrosion, contamination and proper sealing. The cable route and antenna connections should also be inspected, because a fault in the antenna line can appear as unstable indication, loss of ground return or radio altimeter failure. If the system gives incorrect readings, the antennas should be checked together with the transceiver, cables, cockpit indicator and power supply circuits.

Identification and supply of A-037-2

For procurement, the full designation A-037-2 should be used. Alternative names such as A037-2, A-037 antenna or A-037-2 radar antenna can help identify the item, but the exact part number remains the main reference. In a complete A-037 system, two antennas are normally required. Before supply or installation, the antenna should be checked for condition, documentation, connector compatibility and suitability for the required A-037 radio altimeter configuration.

Related components: A-037 Version 10, GU4.137.080-01, GU4.850.567-19. These links are grouped by system and function and do not indicate interchangeability.