With an optional enablement, compatible Garmin avionics can automatically scan and tune up to three additional DME frequencies. Pilots can leverage this multi-channel capability for DME-DME Area Navigation (RNAV), using distance calculations from two or more DME ground stations to determine the aircraft's position for RNAV routes 1. Additionally, the Free Scan Capability 1 allows the system to search for DMEs in range. For integration with legacy distance indicators and navigation radios, GDM 450R also supports legacy databus connections. GDM 4500 for turbine aircraft and helicopters Designed specifically for turbine aircraft and helicopters, the GDM 4500 meets higher qualification levels and is environmentally hardened. Along with Garmin integrated flight decks and TXi displays, it is also compatible with select third party systems, enabled by ARINC 429 support.