RV-5MD1

Operating principle of RV-5MD1

The RV-5MD1 operates as a continuous-wave radar altimeter. The system transmits microwave energy toward the surface below the aircraft, receives the reflected signal and processes it to calculate actual height in real time. The operating frequency band is 4200–4400 MHz. Since the measurement is based on radar reflection from the surface, the system provides true height above land, water or uneven terrain rather than altitude relative to sea level.

Modernized functions of the RV-5MD1 system

Compared with earlier RV-5M configurations, the RV-5MD1 includes functional upgrades in signal filtering, reliability logic and data output capability. Versions equipped with the PP-5M1D1 transceiver can support output compatibility with TCAS / external avionics interfaces, depending on aircraft configuration. This allows radio-height information to be used not only by the cockpit indicator, but also by broader onboard systems where approved by installation documentation.

Complete RV-5MD1 system configuration

A typical RV-5MD1 installation includes the PP-5M1D1 transmitter–receiver unit, two AR5-1 antennas, UV-5M cockpit altitude indicator, RA-5 shock-mount frame, aircraft interconnection cabling and documentation. The PP-5M1D1 generates, receives and processes microwave signals. The AR5-1 antennas provide the transmit and receive paths. The UV-5M indicator displays true radio altitude and supports warning / failure indication in the cockpit.

Altitude indication and warning functions

The RV-5MD1 provides display of true radio altitude on a dedicated cockpit indicator. It also supports adjustable Danger Height presets with light annunciation, FAIL / INOP indication and altitude-triggered pulse outputs. These functions help the crew monitor both actual height and system status during low-altitude operation. If the system fails, loses valid reflected signal or does not pass built-in control, the failure indication warns that the displayed altitude should not be relied on.

Data outputs and avionics integration

The RV-5MD1 can provide analog altitude data and pulse outputs for connected onboard systems. In configurations with the PP-5M1D1 transceiver, the system may also support integration with collision-avoidance and external surveillance systems, including TCAS / RA interoperability. This makes correct configuration especially important: the transceiver version, indicator, wiring, output circuits and aircraft avionics architecture must match the approved installation documentation.

Installation and supply of RV-5MD1

The RV-5MD1 is installed as a complete radio altimeter set. The transceiver is mounted on the RA-5 shock-mount frame, connected to two AR5-1 antennas, the UV-5M cockpit indicator and aircraft wiring. Before supply or replacement, it is important to confirm the required altitude range, indicator type, PP-5M1D1 configuration, antenna set, cabling, external-output requirements and documentation. Passport and maintenance manual should be checked together with the supplied equipment.