Specifications

SECTION III
INSTRUMENTATION AND AVIONICS
MODEL 560
Only one transponder is in operation at one time; the opposite one is held in STANDBY for
instantaneous operation, if required. The system in operation is controlled by the mode select line key.
Pressing the mode select line key (once the cursor is moved to that line) cycles the transponders as
follows:
STANDBY - Both units in STANDBY.
SYSTEM No. 1 in operation.
STANDBY - Both units in STANDBY.
SYSTEM No. 2 in operation.
STANDBY - (sequence will repeat)
The system in operation is indicated by a "1" or "2" in front of the selected mode.
A transponder code may be stored in memory. To accomplish that, select the desired codes and
press the STO button for two seconds. To retrieve the code from memory, press the line select button for
two seconds.
The IDENT function of the transponder may be activated by pressing the ID button on the RMU or by
pressing the ID button on the inboard side of either the pilot’s or copilot’s control wheel. Pressing any ID
button will activate the ID mode for approximately 18 seconds. An amber ID annunciation will appear along
the top edge of the transponder window during ID mode activation.
TRANSPONDER (Optional)
Two Collins TDR-94 transponders, each with 4096 Mode A code capability, are options installed in the
nose avionics compartment. The transponders (1 and 2) have automatic altitude reporting (Mode C)
capability which is provided electronically to the transponders by the respective side AZ-840 Micro Air Data
Computer. The two transponders are controlled by a CTL-92 control on the right side of the center
instrument panel. A switch on the control determines which transponder and altitude source is selected for
operation.
CTL-92 CONTROL PANEL (Optional)
The CTL-92 uses a digital readout to display the pilot selected transponder code. Power and mode of
operation are controlled by the power and mode switch which has OFF, STBY, ON and ALT positions.
STBY applies power to the system for warmup and allows momentary power interruptions which may be
desired without having to turn the system OFF. In ON, the transmitter is enabled for normal operation. ALT
position causes transmission of uncorrected barometric altitude which is supplied by the respective AZ-840
micro air data computer. The 1/2 switch is used to select between number one or number two
transponders.
Two concentric knobs are used to set the code. During normal operation, the upper window will
display the selected code and the lower window will be blank. The lower window is active only during
self-test. The TEST button initiates a system self-test. To test the system, select the desired transponder,
turn the system ON and press the TEST button. The active code will be displayed in maximum intensity,
and if the system is operating properly, ALT will be displayed and the altitude in thousands of feet (5.0 for
5000 feet) will be displayed in the upper window.
An IDENT button is located on the front of the transponder control and one or each control wheel.
Any of the three will activate the IDENT circuit. The IDENT button will cause a distinctive return to appear
on a ground controller's radar screen for 30 seconds after the IDENT button is pressed and released. It
should not be depressed unless requested by a ground controller. The PRE button is used to select a
preset code for storage. The button is pressed in and held while the selector knob is turned to select a
code to be stored. Momentarily pressing the PRE button will recall the stored code.
When codes are being changed, an ACT annunciation will flash in the display. If ACT flashes, the
code being transmitted is not identical to the one being displayed. An annunciation of TX will be displayed
each time the transponder replies to an interrogation. If the transponder malfunctions, diagnostic message
codes will be displayed in the upper window.
I 3-62 Configuration AA 56OMB-01