TCASII TA USED TO EVADE SUSPECTED CONFLICT.

Narrative

ON A FLT FROM (MMTO) MEXICO CITY TO (KELP) EL PASO; TX; WHILE APCHING JUAREZ ON UJ27; UNDER RADAR CONTACT WITH MONTEREY CTR; WE WERE GIVEN; AND READ BACK THE FOLLOWING CLRNC. 'CLRED TO EL PASO VIA UJ27; MAINTAIN (OUR ASSIGNED ALT) EXPECT THE EL PASO 25 DME ARC.' UJ27 IS ON THE 155 DEG RADIAL OF THE JUAREZ (CJS) VOR. WE WERE FURTHER CLRED TO DSND TO 12000 FT. OUT OF APPROX 20000 FT; CTR BEGAN TO ASK FOR OUR DME READOUTS FROM THE CJS VOR. WE GAVE THEM AT APPROX 25 DME; 20 DME AND 16 DME. WE KEPT WAITING FOR CLRNC TO EITHER INTERCEPT THE ELP 25 DME ARC OR THE ELP ARC APCH. NEXT; MONTEREY CTR INFORMED US THAT WE HAD OPPOSITE TFC; OUTBOUND FROM THE CJS VOR ON THE 161 DEG RADIAL; CLBING TO 12000 FT AND ASKED WHAT OUR XING RADIAL WAS? WE RPTED INBOUND TO CJS ON UJ-27 LEVEL AT 12000 FT. WHEN CTR AGAIN ASKED WHAT RADIAL WE WERE XING; WE FIGURED THAT CTR THOUGHT THAT THEY HAD CLRED US TO INTERCEPT THE ELP 25 DME ARC. ABOUT THE SAME TIME; WE PICKED UP THE TFC ON TCASII AT 10 O'CLOCK AND 3000 FT BELOW US. AT 1900 FT SEPARATION; WE GOT A TFC ALERT. WE MADE A R TURN AND INFORMED MONTEREY CTR THAT WE HAD THE EL PASO ARPT IN SIGHT. THEY HANDED US OFF TO EL PASO APCH WHERE WE WERE VECTORED FOR A VISUAL APCH WITHOUT FURTHER INCIDENT.