tuning knobs. The tuning knobs will have no
effect if the transponder is in a standby mode.
When the altitude reporting mode is selected,
the altitude being reported to the interrogating
radar station is displayed on the ATC/TCAS
page (Figure 16-14), which is accessed through
the PAGE MENU page (Figure 16-9).
On the display shown in Figure 16-14, the sec-
ond line from the bottom indicates transpon-
der number one is active and is reporting an
uncorrected altitude of 2,600 feet.
The ATC/TCAS control page (if TCAS II in-
stalled) also allows the operator to temporar-
ily switch the TA display of intruder altitude
from relative (REL) to absolute (FL) by de-
pressing the adjacent LSK. The TCAS display
automatically switches back to REL after 20
seconds. See TCAS in this chapter for more in-
formation.
The selectable modes with a Mode C transpon-
der installed, without TCAS, are as follows:
• STANDBY - Transponder ready, but not
replying.
• ATC ON - Replies on Mode A only (no
altitude reporting).
• ATC ALT - Replies on Modes A and C
(with altitude reporting).
The selectable modes with a Mode C transpon-
der and the optional TCAS I installed are all
of the above, plus:
• TA ONLY - Selects the TCAS traffic ad-
visory mode.
The selectable modes with a Mode S transpon-
der and TCAS II installed includes all of the
above for TCAS I, plus:
• TA/RA (traffic/resolution advisory).
To change the transponder code, first highlight
the code with the cursor. Then, using the large
outer tuning knob, adjust the left two digits;
use the smaller inner knob to change the two
right digits.
A selected transponder code may be stored
into memory by depressing the STO button
while the cursor is on the transponder code.
To retrieve the code from memory, depress
and hold the code line select key for 2 to 3
seconds.
Depressing the ID button of the RMU will ini-
tiate an approximate 18 second IDENT mode
on the transponder. This action will also illu-
minate an ID annunciation along the top edge
of the transponder window (Figure 16-13).
IDENT can also be activated by depressing a
button on the front of the inboard handle of ei-
ther control yoke.
A reply annunciator (rectangular box) is lo-
cated in the upper right corner of the ATC
window. This box will turn amber whenever
the transponder is being interrogated by a
ground station radar (Figure 16-13).
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
16-20
FOR TRAINING PURPOSES ONLY
FlightSafety
international
Figure 16-13. ATC IDENT on RMU