one more thing about TCAS:
In the three types of planes I flew with TCAS,the transponder had to be selected to TCAS position (TA or RA) thus turning on the tranponder & TCAS
should the legacy pilot have turned the transponder off or to stby the legacy pilot would have turned off his TCAS unit denying himself a TCAS warning while cloaking his plane to other TCAS units & ground secondary radar.
unfamiliar with Legacy
thoughts?