Specifications

SECTION III
MODEL 560 INSTRUMENTATION AND AVIONICS
A TX annunciation at the top of the COM frequency window will annunciate whenever the transmitter
is active. When the second (first memory location) page of the display is selected, a "NARROW
BANDWIDTH SELECT" annunciation will appear in the upper right corner of the display. Narrow bandwidth
is the normal selection, however, a wider bandwidth may be selected for use in areas where slightly
off-channel transmitters are used. Its selection will result in improved reception in such areas. The
selection is made by pressing the double arrow selector next to the annunciation. Another press of the
selector will return the selection to the original.
If any of the components of the radio system fail to respond to tuning or operating commands of the
RMU, the frequency or operating command associated with that particular function will be dashed out. This
alerts the crew to a failure or abnormal system operation.
"Cross-side" operation of the RMU is possible by pressing the 1/2 button on the bottom of the RMU.
This allows the operator to tune the opposite side radio system from that RMU. The tuning will be followed
on the other RMU and so indicated. The system banners will be indicated in magenta color to serve as a
reminder of the cross tuning condition.
Each time the integrated radio system is powered up with the landing gear squat switches activated, a
power on self-test (POST) will be activated. If any radio or bus fails any test parameter, an error message
will be displayed on a test results page. If no errors are detected, the main tuning page will be displayed.
A pilot activated self-test (PAST) may be initiated by pressing the TST button on the RMU. A
complete test will then be accomplished on the component represented by the window at which the yellow
cursor is located. At
the completion of the test, a legend will appear in the window for a short time to indicate
successful completion.
If the test is not successful, an error message will appear to indicate which circuit
area has failed. By pressing the DIM button on the bottom of the RMU, the tuning button may be used to
dim the display. Exit from the dim mode is accomplished by pressing the DIM button again. Variations in
ambient light will be automatically sensed, within limits, and automatically adjusted to maintain a desired
setting.
AUXILIARY COM 1/NAV 2 CONTROL DISPLAY UNIT (With Primus II Radios)
The auxiliary COM 1/NAV 2 control display unit is normally located on the center instrument panel next
to the fuel flow/quantity instrument. It may be used in two modes: normal and emergency. The modes are
selected by means of the mode switch on the CDU. The mode selections cycle as the switch is turned. In
the emergency mode, EMRG is displayed vertically along the top right edge of the display. The CDU is
powered from the NAV 2 DC circuit breaker and receives power any time the battery switch is in the BATT
or EMER position.
In normal mode the CDU acts as an additional tuning source for the radio system. COM 1 and NAV 2
may be tuned by the CDU in this mode. The CDU verifies that the COM 1 RCZ-850 or the NAV 2
RNZ-850 (integrated COM and NAV units, respectively) are tuned to the correct frequency by checking the
frequency echoed on the radio service bus (RSB). If the tuned frequency is incorrect, the frequency
displayed on the CDU will be dashed out.
If the appropriate RMU is illuminated, the frequency change will
be seen to appear in the active display. In normal mode, the radios which are tunable by the CDU (COM 1
and NAV 2) may be also tuned from the applicable RMU. If tuned from the RMU, the frequency will also be
tuned on the CDU.
In emergency mode, operation of the CDU is identical on the part of the operator. The internal tuning
of the system differs in that it does not read and compare frequencies on the RSB; whatever frequencies
are set in the CDU are transmitted to the appropriate NAV or COM unit and that frequency is tuned.
When tuning the CDU, COM frequencies are displayed on the top line and NAV frequencies on the
bottom. An arrow cursor, which appears to the left of the displayed frequencies may be toggled between
the NAV and COM frequencies by pressing the double arrow (transfer) switch. The line on which the arrow
appears is then tunable by the tuning knobs on the CDU.
I 56OMB-01 Configuration AA 3-19