RADIO MANAGEMENT UNITS
General
The radio management units (RMUs) are the
central control units for the radio system. They
provide complete capability for controlling
the operating mode, frequencies, and codes
within all the units of the radio system. Either
RMU can be used to control frequencies/modes
for NAV, COM, ATC and ADF. The TCAS (if
installed) is also controlled through the RMUs.
COM 1 and NAV 1 frequency control is also
available through the clearance delivery unit,
which is described later in this section, and
through the FMS, if installed.
When a radio is tuned with either RMU, FMS
or the clearance delivery head, the selected fre-
quency or code is echoed back to all of these
units after the frequency/code is changed, so
they all reflect the current setting.
The RMU has a color LCD (liquid crystal dis-
play) and uses the concept of pushing a line
select key adjacent to the parameter that the
crew wishes to control (Figure 16-8). Any se-
lectable parameter, such as a VOR frequency
(NAV), may be changed by first depressing the
line select key adjacent to the displayed fre-
quency. This action places a yellow cursor
box around the frequency. Rotating the con-
centric tuning knobs, at the lower right, will
then set the desired value.
There are six keys on each side of the RMU.
The top key on each side is referred to as a
transfer key, and has up and down pointing ar-
rows on them. The remaining keys are referred
to as line select keys. The RMUs also contain
eight function keys located at the bottom, to
the left of the tuning knobs.
The RMU main tuning page (Figure 16-8) is di-
vided into six dedicated windows. Each window
groups the data associated with a particular func-
tion. The windows (COM, NAV, ATC/TCAS,
ADF, and TCAS DSPY) each provide for con-
trol of both frequency and operating mode of the
associated function. The ATC and TCAS win-
dows will vary depending on which optional
equipment is installed.
The RMU also has other display modes, called
pages, which provide additional features and
functions for the control of the radio system.
The PGE function key at the bottom of the
RMU is used to access additional RMU pages.
When the PGE function key is depressed, a
PAGE MENU page will be displayed (Figure
16-9). The desired page is then selected by de-
pressing the line key adjacent to the selection.
RMU display brightness is adjustable using the
tuning knob after the DIM function key is de-
pressed. To return the tuning knob to normal
operation select any other key. Setting dis-
play brightness provides the bezel mounted
light sensors with the pilot’s desired refer-
ence about which they adjust the brightness for
varying lighting conditions.
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
16-14
FOR TRAINING PURPOSES ONLY
FlightSafety
international
Honeywell
TUNE
SQ
DIM
1/2
STO
DME
TST
PGE
ID
COM 1
NAV 1
ATC/TCAS
ADF 1
TCAS DSPY
123.20
131.27
MEMORY-3
1471
1 ATC ON
RANGE:
40
BELOW
110.25
109.35
MEMORY-1
162.5
ANT
NB
Figure 16-8. Radio Management Unit