Forgein worker :my remark about stessed japanese controllers was supposed to be a joke, not a racist remark ! I have to watch my language in the future. my apologies.
I never said TCAS was unreliable but TCAS was never made to be a CDTI ( Cockpit display of traffic info ) is is a software logic aimed at issuing warnings to prevent a collision in last minutes close encounters. The display is an add on that was not even specified in the early certification process.
The poor azimut detection at large distances is a early, known deficiency but that does not alter the anti collision logic.
again TCAS should not be used to identify traffic.
As a controller I would add " never " and a pilot suing R/T sentences like " I see him on TCAS " will get him in trouble one day.
TCAS is a last minute anti collision device and should not be used for anything else.
The Collision avoidance logic (CAS) has also its flaws, especially in issuing reversals, (and Ueberlingen is a perfect example of this), but that is another story.
Ah, and a 50-60 degree turn can be odd, I grant you that ..