Specifications

SECTION III
INSTRUMENTATION AND AVIONICS
MODEL 560
NAV 1 or NAV 2 will be annunciated on the top line of the indicator to indicate which NAV is being
displayed and computed. If the DME is being held, HLD is annunciated on the top line along with NAV 1 or
NAV 2 to indicate which channel the DME is holding. When a station is being held, the regular functions
are selectable on the DI-850 indicator and information will be computed from the station identified by “H” on
the DME line of the RMU; however, after 15 seconds, the DI-850 annunciation will revert to identifier.
The select (SEL) button on the indicator is used to cycle the display on the right side of the readout
through ground speed, time-to-station, and IDENT functions. If HOLD is selected on the DME, the function
will return to IDENT in 15 seconds if any other function is selected.
The DME has a "split tuning" mode which operates somewhat like conventional HOLD functions, but
provides other options. Pressing the DME button on the bottom of the RMU will divide the NAV window
into two windows. The top window will remain the active VOR frequency. H will be annunciated on the
bottom line, indicating that the DME frequency is holding with the active frequency which is displayed on
the top line. The bottom line will be labeled DME and will have in it the active frequency displayed in VHF
(VOR) format. The DME may then be tuned by pressing the line select key and changing it to a new
channel. Pressing the DME button again will cause the DME (lower) window to change to a TACAN
channel presentation. TACAN channels, along with their related W, X, Y, and Z channelization
nomenclature will then be tunable with the tuning knobs. The DME function of all 126 TACAN channels
may be tuned. No azimuth information is received in this mode. A third press of the DME button causes
the NAV window to return to its normal active/preset presentation and the DME will resume tuning with the
active frequency.
DME information is displayed on the pilot's and copilot's EHSIs by pressing the NAV button on the
DC-550 Display Controller. Pressing the NAV button alternately selects NAV 1 and NAV 2 for display. If
both NAV receivers are selected to the same NAV source, the NAV annunciations (VOR 1, VOR 2) on the
EHSI will be in amber. The selected DME will always be the same as the NAV source (VOR). If no DME
information is available, the DME readout will display amber dashes.
DME-442 WITH IND 42C INDICATORS (Optional)
The optional DME installation consists of two DME-442 receiver-transmitters and two IND-42C
indicators. The IND-42C is an indicator only and does not control selection of DME data for any purpose
other than selection of the data to be displayed on the indicator. Nav 1 is permanently connected to the
pilot’s DME-442 indicator and NAV 2 is permanently connected to the copilot’s DME-442 indicator.
DME information is displayed on the pilot's and copilot's EHSIs by pressing the NAV button on the
DC-550 EFIS display controller. Pressing the NAV button alternately selects NAV 1 and NAV 2 for display
on the respective EFIS. If both NAV receivers are selected to the same NAV source, the NAV annunciation
(VOR 1, VOR 2) will be in amber. The NAV source (VOR) displayed and annunciated on the EFIS display
will always be the same as the DME selected by means of the NAV button on the DC-550 display controller.
Selections made on the IND 442 indicator have no bearing on the EFIS display.
Figure 3-29. Primus II DI-850 DME Indicator
I 3-64 Configuration AA 56OMB-01