Revision A
T-48 90 008 026
2-13
During any test in the manual mode of operation, the operator may chose to repeat a particular test by
toggling the
STORE/REPEAT
switch. The current test displayed will commence again. The operator may
continue doing this as long as the Test Set remains “ON”. Turning the Test Set “OFF” and then “ON” will
require the operator to go through all previous tests again to reach the desired test they want to repeat. By
leaving the switch in
REPEAT
, the test set will continue testing until toggled back to
STORE.
Always
return the
REPEAT
switch to
STORE
when testing is completed. If left in the
REPEAT
position, the Test
Set cannot be turned
OFF.
2.11.3 Mode S Automatic Sequence of Transponder Tests
Figure 2-6 lists the sequence of tests performed with a Mode S equipped transponder under test. Paragraph
2.11.4; Mode S Manual Sequence of Transponder Tests, describes in detail, each test performed. When the
INTERROGATE
button is depressed, the sequence will continue as long as normal results are received
for each test. If an abnormal result occurs, the sequence will stop at that test and a “FAIL” message will be
displayed. To override after a “FAIL” message, depress the
INTERROGATE
button to continue testing
with the failure.
First display shown once the T-48 has determined a Mode S equipped
transponder is being received.
When selecting the Automatic sequence of tests, the results of the tests will not be displayed until the final
test is completed. At that point, the POWER, RCVR & FREQ display will be shown and testing will end
until the
INTERROGATE
or
TEST
buttons are depressed again to initialize another series of tests.
NOTE
The final display of Mode S Transponder tests alternates between two
(2) pages. The first page indicates the 4096 octal code, the decoded
aircraft address, aircraft altitude and power, sensitivity, and frequency
measurements.
The second page displays the aircraft address in both Hexadecimal and
Octal, power measured in watts and the decoded Flight Identity.
In the Automatic sequence of tests, “MAX TRUE AIRSPEED” and “VERTICAL STATUS BIT” tests are
omitted. In addition, the operator will be unable to verify the UUT “IDENT” function. Pulse Width, Pulse
Spacing and Data Pulse measurements are performed during the Automatic Sequence of tests. Utilize the
Manual sequence of tests to verify a transponders “
IDENT
” function.
MODE S XPDR COM/AB
INTERROGATE TO TEST
H:YYYYYY O:XXXXXXX
250W FID:DLXXXXXX
4457 NXXXXX 10,000’
54dB-75dB 1090.0MHz
Typically
, for U.S. civilian aircraft having MODE S addresses assigned, the number of
the aircraft will be displayed. For non- U.S. and military aircraft, the MODE S address
will appear as a Hexadecimal proceeded by the letter “N”. If a Hexadecimal address is
displayed for a U.S. civil aircraft, this may indicate an incorrectly wired transponder. In
the manual mode of MODE S tests, all addresses will be displayed in Hexadecimal.
