SMA INSTRUCTOR HAS NMAC WITH HELI IN TFC PATTERN AT UNCTLED ARPT.

Narrative

WHILE ON A R DOWNWIND DEP AT CGZ (RWY 5); A HELI PASSED L TO R JUST UNDER AND AHEAD. WE HAD JUST FLOWN THE ILS AND WERE MISSED VECTORS FOR ANOTHER APCH. THE TFC WAS LIGHT FOR CGZ; USUALLY 5-12 ACFT WANTING THE SAME AIRSPACE FOR APCHS. TODAY; THERE WERE ONLY 3 OF US. I MENTION THAT BECAUSE I DO NOT RECALL HEARING THE HELI ON THE RADIO AT ANY TIME. USUALLY; ACFT; INCLUDING THE HELIS THAT DO LAND AT CGZ CALL WHILE ON OR LEAVING FROM THE RAMP. I TRIED TO REACH HIM ON THE RADIO; BUT NO RESPONSE. THERE WAS NO EVASIVE ACTION ON HIS PART; SO I ASSUME THAT HE NEVER SAW ME; NOR WAS HE TALKING. IT APPEARS THAT HE DEPARTED S; TURNED 180 DEG AND WAS HDG N TO OVERFLY THE FIELD AT 3500 FT. THAT WAS CONFIRMED AFTER TALKING TO OTHERS ON THE GND ABOUT HIS DEP RTE. THAT RTE OF DEP IS VERY RISKY BECAUSE OF NUMEROUS ACFT FROM A LARGE TRAINING FACILITY NEARBY THAT USES THE KPIN RADIO STATION FOR AN NDB APCH; WHICH FINAL APCH COURSE IS DIRECTLY IN LINE WITH THE HELI'S DEP PROC. I HAVE HAD SEVERAL 'CLOSE ENCOUNTERS' WITH SMALL SINGLE ENG ACFT TRANSITIONING THE CASA GRANDE AREA WITHOUT LISTENING OR AT LEAST RESPONDING ON THE RADIO. BECAUSE OF THE VOLUME OF TRAINING THERE; IT IS QUITE DANGEROUS; EVEN IF ONE IS FAMILIAR WITH THE LCL (INSTRUCTOR'S) PROCS AND RPTING POINTS. THERE CURRENTLY IS NOT A HIGH VOLUME OF HELI TFC; BUT THAT MAY CHANGE IF THE CITIES OF PHOENIX AND TUCSON COMBINE 'EVAC' SVCS TO CASA GRANDE. IF THAT IS THE CASE; THEN LCL STANDARD ARR/DEP PROCS MUST BE INCORPORATED AND UNDERSTOOD BY EVERYONE.