User's Manual

FLITELINE AVIONICS SYSTEM
PILOT’S GUIDE
Publication No. 150-047012 Page 31
Rev. D Dec 2005
The SD-442 has only three controls. Each is a
momentary, spring-loaded type that releases when
finger pressure is removed. On-off power is through
an external switch such as a radio or avionics
master switch, or a dedicated DME switch. Volume
control of DME station identification audio is also
external, typically located on an audio panel.
NAV - Alternately places annunciator 1, 2, or RNV
in display.
1 - Selects NAV System 1 as the controller of
the DME channel.
2 - Selects NAV System 2 as the controller of
the DME channel.
RNV - Allows the SD-442 Selector Display to be
used as a "repeater" display or
RNAV-computed distance to a waypoint
and ground speed. This allows RNAV
data to be available during times it might
not be displayed by the RNAV System (for
example, when other data is selected for
display on some types of RNAV's).
HOLD - Pressing and releasing this switch does the
following:
A. Locks the appropriate channel of the DME
frequency in use. Aircraft wiring will affect
the way in which the hold feature works. In
some installations, pin 58 ground, the hold
switch will only place the corresponding
channel in hold. In others, pin 58 open, the
hold switch will place the displayed channel
into hold.
B. Displays the current NAV frequency that
determines the DME channel.
C. Disconnects control of the DME from the
NAV Receiver.
D. Displays annunciation HLD.
The purpose of this switch is to allow the
NAV Receiver to be set to other frequencies
without affecting DME operations. The DME
continues to function on its "holding" channel.
Pressing and releasing this switch while in
the HLD mode will return control back to the
indicated NAV System (1 or 2).