ing chart (para 3-18).
3-13. Stopping Procedure
(4) Set mode and prearranged code settings fa
To stop the AN/APM-123A (V), release the PRESS
modes 2 and 3/A and test as above.
TO TEST switch if it is in LOCK position and set the
(5) Preset equipment as described in paragraph
28 VDC-115 VAC-OFF power switch to OFF.
3-12c, 3-12d, and 3-12e. Request interrogations in
each mode of operation and obtain results from inter
3-14. Alternate Performance Check
rogation facility. Positive results indicate equipment
To perform the alternate performance check, pro-
is operating normally. If results are negative, recheck
ceed as follows.
switch settings and if found correct, refer to troubh
a. Preliminary Procedures.
shooting chart (para 3-18).
(1) Apply external power to aircraft (para 3-9a).
(2) Energize aircraft radio and contact local GCA
3-15. Periodic Preventive Maintenance
facility or organization having an RT-859/APX-72
Checks and Services
interrogation capability. Use locally assigned and
In addition to the intermediate preventive maint~
approved frequency channel.
nance checks and services, periodic preventive main
(3) Set the RT-859/APX-72 and C-6280 (P)/APX
tenance checks and services will be scheduled in
switches in accordance with table of paragraph 3-12a.
accordance with the requirements of MIL-M-23618
(WEP) (Navy), TM 38-750 (Army), and AFR-66-12
Due to close proximity of local interrogation
facility, it would be advisable to place
(Air Force). The RT-859/APX-72 will normally be part
of an aircraft installation. The periodic preventive
MASTER control of C-6280(P) /APX on
maintenance checks and services should be schedule
LOW rather than NORM to reduce the RT-
concurrently with the periodic maintenance service
schedule of the aircraft in which the equipment is in
b. Systems Tests.
stalled to reduce out-of-service time to a minimum.
Refer to the applicable aircraft technical manual for
Code settings used for these tests should be
the hours between service periods. All deficiencies
standard, prearranged codes, known to both
or shortcomings will be immediately reported to
maintenance presonnel and operators of the
higher category of maintenance by use of NAV
transponder system interrogation equipment.
WEPS Form 13070/5 (Navy), TM 38-750 (Army), an
(1) Set prearranged mode 1 code settings into C-
AFTO Form 29/29A (Air Force). Equipment that
cannot be corrected by organizational maintenance
(2) Request interrogation of RT-859/APX-72 by
should be deadlined in accordance with applicable
local interrogating facility on mode 1 using same
directives. Perform all checks and services listed in
the periodic preventive maintenance checks and ser-
(3) Request results of interrogation. Positive
vices chart (para 3-16) in addition to the intermedial
results indicate equipment is operating normally.
preventive maintenance checks and services chart
If results are negative, recheck mode and code
switches and if found correct, refer to troubleshoot-
3-16. Periodic Preventive Maintenance Checks and Services Chart