Install Manual Part 3

SKY497
Installation Manual
C-2
Rev. C
C.3 CHECKOUT PROCEDURE
The T-49C Flightline Tester simulates a ground based secondary surveillance radar (SSR) when the TCAS
INTRUDER selector switch is in the ATCRBS/Mode-S XPDR TEST position. When the T-49C intruder
type switch is set to ATCRBS, the unit responds to ATCRBS Mode C interrogations. A varying delay time,
controlled from the microprocessor, delays the replies returned to the SKY497 from as far as 14 nautical
miles and as close as a few hundred feet. The apparent distance from the simulated intruder to the
SKY497 system under test decreases as if the intruder was converging on the aircraft under test. The test
set determines the altitude of the aircraft under test by interrogating the transponder using an ATCRBS
interrogation. By adding or subtracting the desired differential altitude, as selected by the front-panel
scenario switch, the initial altitude of the scenario is controlled by the microprocessor. This altitude, like
the distance, is varied so that the simulated intruder converges on the aircraft’s position.
1. Make sure the aircraft's transponder is in the STBY mode and the DME is turned OFF. At the
aircraft's instruments, verify all compass/HSI flags are valid.
NOTE
After power up, it may take a couple of minutes for the altitude encoder to
return a valid altitude to the transponder and SKY497.
2. Turn SKY497 ON. The display will show a start-up screen similar to one shown in figure C-2. After
start-up screen appears, rotate the OFF/BRT switch. Verify that clockwise rotation increases display
brightness.
Figure C-2. Start-up Screen
After approximately thirty seconds the display will show the STANDBY screen (see figure C-3).
NOTE
If the TRC has not been calibrated to the directional antenna (see step 4
below), the display may show a “SKY497 FAILED” message.