ATR 42
 

This is a question for ATR drivers. We have two TACAS displays on the ATR, with a selection of above and below. It increases the scope of detection, from 2700 to 9900. If the one selector is set to above and the other to below, would the coverage increase to 9900 to 9900. There is only one TACAS with two antennae so theoretically the range should remain of the the master display. The one which is on the side of the active coupling. Am i right ?

No, the display is just a display and does not affect the alerting logic.


At least that is how i understand it.

PT6A

Assuming the ATR has the same TCAS setup as the DHC8's, the ADV setting gives 9900 above and 2700 below, while BLW gives 9900 below and 2700 above. The "middle" setting (not ABV or BLW) gives 2700 above and below. The DHC8 has one TCAS controller and two screens (100-300).

I agree with PT6A :ok:

PT6A is correct. The above, below, and range selections on the ATR's TCAS displays are only for decluttering (particularly in busy airspace) and do not affect the TCAS's alerting logic. TCAS detects traffic farther out than 12 NM (I cannot recall the exact distance right now). The main alerting parameter is time to closest point of approach.

Also, the displays for the TCAS are only displays, so there is no master display.The only way you can affect TA generation is to turn the TCAS (or your transponder) off.

I hope this helps.

thanks guys