A C210 PLT EVADED A PA28 ON A PRACTICE ILS IN A CTAF TFC PATTERN AT CXO.

Narrative

THE OTHER ACFT WAS ON A PRACTICE ILS APCH TO RWY 14 AND GAVE HIS POS ON THE ILS. THERE WERE 4 ACFT IN THE PATTERN. I ENTERED DOWNWIND AT THE 45 DEG ENTRY; S OF ILS TO ACTIVE RWY 1; AT PATTERN ALT AND RPTED MY POS. I HAD A VISUAL ON THE PIPER ACFT UNTIL ON DOWNWIND; I RPTED MY POS ON DOWNWIND WITH MY INTENT TO MAKE A FULL STOP LNDG. WHILE EXTENDING THE GEAR AND FLAPS; THE PIPER PLT RPTED THAT HE INTENDED MAKING A 270 DEG TURN AND ENTER DOWNWIND FOR LNDG RWY 1. AFTER EXTENDING FLAPS TO 20 DEGS; I RPTED TURNING DOWNWIND TO BASE RWY 1; AND STARTED DSNDING TURN TO BASE. DURING THIS TURN THE PIPER PLT RPTED THAT HE WAS ON L BASE LNDG RWY 1. I RAISED THE WING AND OBSERVED THE PIPER ACFT IN A DSNDING TURN INSIDE AND BELOW MY POS. I TOOK EVASIVE ACTION WHILE HE CONTINUED HIS APCH AND LNDG. CAUSE: THE FLT INSTRUCTOR AND STUDENT ON A PRACTICE APCH; AT THE MIDDLE MARKER; TURNED R; AND CLBED IN THE DOWNWIND TFC PATTERN. THE INSTRUCTOR DID NOT MAKE THE 270 DEG TURN AS HE STATED; DID NOT ATTAIN PATTERN ALT OR MAINTAIN ACFT SEPARATION. PREVENTION: INSTRUCTOR PLTS SHOULD TEACH AND USE STANDARD PROCS AT UNCTLED ARPTS.