Specifications

SECTION III
MODEL 560 INSTRUMENTATION AND AVIONICS
DISTANCE MEASURING EQUIPMENT
HONEYWELL PRIMUS REMOTE RADIO SYSTEM - DME
The Primus II DME system ,the standard DME installation, is comprised of systems which are
organized into compact modules. Each module, concerning the DME system, is comprised of an RNZ-850
integrated navigation unit, an NV-850 VHF NAV receiver and a DME-850 distance measuring module. The
DME transmitter of the DME-850 works in the L frequency band, and the receiver frequency range is from
962 to 1213 MHz. DME tuning normally follows the VHF NAV receiver tuning which selects the DME
frequencies paired to the VHF VORTAC published frequencies. The PRIMUS II, however, has a special
"hold" function which also allows the tuning of military TACAN channels in order to receive the DME portion
of the TACAN signals.
The DME has the capability to scan six channels, simultaneously tracking four selected DME channels
for distance, ground speed and time to station, as well as tracking two stations for identification (IDENT)
functions. Of the four channels of which it can track three functions (DIST, GS and TTG), two are
dedicated to the flight management system (FMS).
Normally, one DME station will be tuned to an active VOR frequency, which is annunciated on the top
line of the NAV tuning window of the radio management unit (RMU). Another (preset) VOR frequency may
be selected in the preset frequency window. When a frequency is set in the preselect window, the system
will already be tracking the preselected station so that there will be no delay when that frequency is
transferred to active.
NAV tuning, which normally also selects the associated DME frequencies, is discussed under PRIMUS
REMOTE RADIO SYSTEM - NAV in this section. Special tuning procedures applicable to DME, which are
in addition to the NAV tuning, are discussed below.
Two DI-850 indicators are installed; one on the pilot's instrument panel and one on the copilot's
instrument panel. DME information is presented on the DI-850 DME indicator and, when selected on the
DC-550 display controller, on the pilot's and copilot's EHSIs. The channel (CH) button allows selection of
NAV 1 or NAV 2 on either DI-850 indicator; each indicator can be selected to its own side or the opposite
side. Selections on the CH button on the indicator will not affect the selection(s) made on the DC-550
Display Controller, which controls the display on the respective EFIS. A selection on one DI-850 indicator
will not affect the selection on the opposite indicator.
Figure 3-28. CTL-92 Transponder Control Panel
I 56OMB-01 Configuration AA 3-63