Originally Posted by
Clinton McKenzie
Depending on the airport, some functionalities of TCAS are ‘inhibited’ by some crews on approach and departure. Some airports in the world are really, really busy. The content of 43’s post you quoted was probably an over-statement, but it’s not entirely inaccurate.
Depends on the fitment but generally TCAS will only show up to TAs once below a certain altitude. Its not generally a crew choice, its programmed into the system. You will still get a display of TAs and proximates. And in busy situations other and proximate locations can be a bit iffy on the display, most just a 'look here' type of thing rather than a radar you can use to avoid things. Aurals are also inhibited, for the reasons stated above about excessive distractions.
I think it comes back to the idea that traffic displays are a technology you can use in advance to identify threats and initiate communication to avoid conflict via radio and see and avoid. Again in a busy circuit its a distraction that will not help much.
And it cant be stressed enough that transponders fail or can be turned off, then the target will be invisible to any traffic display or ACAS.