VOR / ILS / MB (VHF-NAV) AND DME – GENERAL
The navigation and communication subsystem includes:
• VOR/ILS (VHF Omni-Directional Radio Range /Instrument Landing
System) navigation
• DME (Distance Measuring Equipment) navigation
The Modular Radio Cabinets (MRC) contains the VOR/ILS (VIDL), the DME
and the Network Interface Module (NIM). The NIM gives processing
functionality and interface with the ASCB databus. The NIM interfaces with
the audio panels by way of the digital audio and microphone buses. The
radios are controlled using the MCDU and PFD radio tuning functions. The
pilot intercom function and the control of audio from the radios are given by
the audio panels.
The VHF-NAV provides for:
• VOR lateral deviation
• TO/FROM flag
• VOR bearing and audio
• ILS (LOC+GS) deviations and audio
• MARKER BEACON annunciator and audio
The DME is connected to the display system and to the Flight Management
System through the Avionic Standard Communication Bus (ASCB-D). The
digital audio bus transmits the DME identification audio signals to each audio
panel. The DME operates with radio pulses in the frequency range from 960
MHz to 1215 MHz. The airborne system transmits from 1025 MHz to 1150
MHz to a ground station. The receiver frequency range is from 962 MHz to
1213 MHz.
The DME provides for:
• distance from the ground station
• ground speed and time-to-station
VHF-NAV AND DME – MAIN COMPONENTS
The VHF-NAV main components are
• two VHF-NAV modules (inside MRC 1 and MRC 2)
• one VOR/LOC antenna
• one GS antenna
• one MB antenna
• three antenna couplers
The DME main components are
• one DME module (inside MRC 2)
• one DME antenna
VHF-NAV AND DME – TUNING AND MODE SELECTION
VHF-NAV and DME tuning can be performed via MCDU or CCD; selection of
mode of operation can only be performed via the MCDUs.
See chapter 23-00 for further details on tuning and memory setting.