2. MODES 1 and/or 3A code selector buttons
Press and release until desired code shows.
3. TEST, TEST/MON, and REPLY indicators
Do not make any checks: (1) near a radar
site; (2) with MASTER control switch in
EMER, or (3) with M-3/A codes 7600 or
7700 without first obtaining authorization
from the interrogating stations.
4. If MODE 1, M-2, M-3/A, 0r M-C is to be used,
check as follows:
a. MASTER control switch NORM.
b. ANT selector switch TOP.
c. M-1 switch Hold at TEST. Observe that
TEST GO indicators are on.
d. M-1 switch Return to ON. If MODE 2, 3/A,
or C are to be used, check as follows:
(1) M-2, M-3/A, and M-C switches Repeat
steps (4c) and (4d).
e. ANT switch BOT.
f. Repeat steps (4c) through (4d(1).
g. ANT selector switch DIV.
h. Repeat steps (4c) through (4d(1).
This procedure utilizes bit to perform a self-
test on the AN/APX-100 IFF. Because bit
cannot test the KIT-1A/TSEC, this test will
only verify the operational readiness of the
IFF in MODES 1, 2, 3/A and C.
5. If MODE 4 is to be used, check as follows:
a. MODE 4 CODE selector switch position A.
b. MODE 4 AUDIO/LIGHT/OUT switch OUT.
c. MODE 4 TEST/ON/OUT switch TEST. Ob-
serve that TEST GO indicator lights and
MODE 4 REPLY indicator does not light.
d. MODE 4 TEST/ON/OUT switch ON.
When possible, request permission from in-
terrogating station to activate radar test
6. RAD TEST switch RAD TEST and hold.
7. RAD TEST switch Return to OUT.
8. Verify from interrogating station that TEST
MODE reply was received.
3.17.4 Normal Operation.
Completion of the starting
procedure leaves the APX-100(V) in operation. The fol-
lowing steps may be required, depending upon mission.
Due to possible operating problems of
the (IFF), usage of the UHF radio on fre-
quency ranges 341.325 thru 345.325 is
prohibited while operating the IFF in
a. Normal Mode.
1. MODE 4 CODE selector switch A or B as re-
a. If MODE 4 code retention is desired, after
landing and before turning the MASTER
control switch OFF or helicopter power off,
place the MODE 4 CODE selector switch to
HOLD and release. Allow approximately 15
seconds for the HOLD function to operate
before turning the MASTER control switch
OFF or helicopter power off.
b. If MODE 4 code retention is not desired, ei-
ther place the MODE 4 CODE selector
switch to ZERO or with the helicopter on the
ground turn the MASTER control switch
OFF. For both methods zeroizing is immedi-