Install Manual Part 2

SKY497
Installation Manual
3-2
Rev. C
3.3. CHECKOUT PROCEDURE
The TT391 Flightline Tester simulates both a ground based secondary surveillance radar (SSR) and an
airborne transponder. With the SKY497 set to GROUND TEST (i.e., the barometric altimeter is simulated
to 50,000 ft, heading simulated to 0 degrees, and the radar altimeter simulated to 2,500 ft) the TT391 will
simulate two targets; a Traffic Advisory (i.e., a solid circle) at ¼ nm and Other Traffic (i.e., open diamond)
at 4.5 nm. Both targets will be displayed in level flight at own aircraft altitude (i.e., "00" displayed above
the traffic symbol).
If the indications given in the following procedure, except for the Flightline Tester, are not obtained, refer
to the troubleshooting procedures in Chapter 4. If indications given for the Flightline Tester are not
obtained, refer to the maintenance section of the TT391 Instruction Manual.
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 3-2. After
start-up screen appears, rotate the OFF/BRT switch. Verify that clockwise rotation increases display
brightness.
Figure 3-2. Start-up Screen
After approximately thirty seconds the display will show the STANDBY screen (see figure 3-3).
NOTE
If the TRC has not been calibrated to the directional antenna (see step 3)
the display may show a “SKY497 FAILED” message.