Originally Posted by Capt Pit Bull
If you are TCAS equipped you most definitely should NOT select standby as you will disable your TCAS. It will have to rebuild its roll call and tracking when you turn your transponder back on. Since you are getting code changes around the same time as RT freq changes and FIR / sector boundaries which are obviously already risk factors, knocking a hole in your TCAS protection is not a good idea.
Is this strictly correct?
I thought that if you switch the tx'der to STBY other aircrafts' TCAS would lose your target but your TCAS would continue to track others nearby. Without your tx'der input, I assumed that you would still get TAs on other traffic (but no RAs).
Maybe I've got it all confused somewhere - I've only ever seen it working for real briefly (or only looked at it briefly when I've been up front on a flight) so I'm only going from reading etc.