After 3 or 4 seconds, simulated lightning test pulses are
sent to the display.
Verify that a rate symbol is displayed at
25 nautical miles, at 45 degrees to right of center. This
symbol will take approximately 5 to 7 seconds to build
This time will be extended to approximately 15 seconds
if TST is selected immediately from OFF, due to
lightning processor initialization.
The symbol's range may vary by as much as 5 nautical
miles if strong local interference is present.
Verify that a magenta lightning alert
symbol is displayed at maximum selected range, at 45
degrees right of center. This must remain on display for
3 to 7 seconds.
To restart the test switch to LX mode
and back to CLR/TST mode.
If the power-on test or the on line built-in test
equipment detects a fault, either prior to or during the
operation of self test, the system will switch the
displayed mode symbol to an amber LX/F. A special
fault message may be obtained by switching to the
CLR/TST mode. In the CLR/TST mode an amber LXmn
will be displayed, where mn is a failure code that may
be interpreted according to table 3-13.
Lightning Sensor System Normal Operation.
control panel) -LX
Range switches (radar control panel) -
Set desired range.
If radar system mode selector switch is set to OFF, LSS
range will revert to 50 nautical miles.
3-33. TRANSPONDER SET (APX-100).
receives, decodes, and responds to interrogations from
air traffic control (ATC) radar to allow aircraft
identification, altitude reporting, position tracking, and
emergency tracking. The system receives a frequency
of 1030 MHz and transmits preset coded reply pulses on
a frequency of 1090 MHz at a minimum peak power of
200 watts. The range of the system is limited to line-of-
sight. The transponder system consists of a combined
receiver/transmitter/control panel (fig. 3-34) located in
the pedestal extension; a pair of remote switches, one in
each control wheel; and two antennas, located on the
underside and top of the fuselage. The system is
protected by the 3-ampere TRANSPONDER, and 35-
ampere AVIONICS MASTER PWR No. 1 circuit
breakers on the overhead circuit breaker panel (fig. 2-
Functions (fig. 3-34).
TEST-GO indicator. illuminates to
indicate successful completion of built-in-test (BIT).
TEST-MON indicator. Illuminates to
indicate system malfunction or interrogation by a ground
ANT switch. Selects desired antenna
for signal input
TOP. Selects upper antenna.
Selects diverse (both)
BOT. Selects lower antenna.
RAD TEST-OUT switch. Enables reply
to TEST mode interrogations from test set.
MASTER CONTROL. Selects system
OFF. Deactivates system.
STBY. Activates system warm-
up (standby) mode.
EMER. Transmits emergency
STATUS ANT indicator. Illuminates to
indicate the BIT or MON fault is caused by high VSWR
KIT. Illuminates to indicate the BIT or
MON fault is caused by external computer.
STATUS ALT indicator. Illuminates to
indicate the BIT or MON fault is caused by the altitude