AR5-1

Transmit and receive function of AR5-1

A standard radio altimeter installation normally uses two AR5-1 antennas. One antenna is used for transmission of the microwave signal toward the ground or water, while the second antenna receives the reflected signal from the surface. This two-antenna arrangement supports continuous radar altitude measurement and helps maintain separation between the transmitting and receiving paths. The received signal is then routed to the electronic units of the radio altimeter for further processing.

AR5-1 with A-037 system components

The AR5-1 antenna operates with A-037-1 series transceivers and A-034-4 series cockpit indicators, depending on the installed RV-5M or A-037 configuration. The transceiver generates and processes the microwave signal, the antenna provides transmission and reception, and the indicator displays altitude and warning information in the cockpit. For replacement or supply, compatibility should be checked by the installed radio altimeter variant, transceiver type, indicator version, cable set and aircraft documentation.

Role in true altitude measurement

In the radio altimeter system, the AR5-1 forms the directional radiation pattern needed for downward microwave coverage. The transmitted signal is directed toward the surface under the aircraft. After reflection from land, water or uneven terrain, the receiving antenna captures the return signal. The system then compares the transmitted and received signals and forms true altitude data. The AR5-1 is therefore a critical external element of the measuring path, even though all computation is performed inside the electronic units.

External installation on the airframe

The AR5-1 antenna is mounted externally on the aircraft fuselage or airframe in positions defined by the approved installation documentation. Correct downward orientation is important because the antenna must provide unobstructed coverage of the surface below the aircraft. Installation should avoid shielding by structural elements, covers, equipment, incorrect fairings or damaged mounting areas. A poor antenna location or damaged cable path can affect radio altitude indication and warning reliability.

Inspection and service notes for AR5-1

During maintenance, the AR5-1 should be inspected for mechanical damage, corrosion, contamination, secure attachment, connector condition and sealing integrity. The antenna cable route should also be checked, because cable damage or poor connector contact can cause unstable indication, loss of reflected signal or radio altimeter failure warnings. Since two antennas are normally used, both transmitting and receiving positions should be checked as a pair when troubleshooting the radio altimeter system.

Identification and supply of AR5-1

For procurement, the full designation AR5-1 should be used. Alternative references such as AR-5-1, AR5 1 antenna or AR5-1 A-037 antenna can help identify the item in correspondence, but the exact designation should remain the main reference. Before supply, it is useful to confirm the target system, aircraft type, antenna quantity, condition, connector compatibility and documentation. In most RV-5M / A-037 installations, two antennas are required for one complete system.

Related components: A-037 Version 11, GU4.137.080-01, GU4.850.567-19. These links are grouped by system and function and do not indicate interchangeability.