C172 FLT INSTRUCTOR; WITH STUDENT PLT; TOOK CTL OF ACFT DURING DOWNWIND LEG TO MAKE AN EVASIVE CLBING TURN TO AVOID ANOTHER C172 XING THROUGH THE TFC PATTERN ON A COLLISION COURSE.

Narrative

ACFT #1 WAS A STUDENT PLT TRAINING FLT OPERATING AT THE BRINKMAN PVT ARPT WITH THE OWNER'S PERMISSION. I WAS THE FLT INSTRUCTOR; INSTRUCTING THE STUDENT IN ARPT TFC PATTERN PROCS. AS WE TURNED DOWNWIND FROM XWIND; I OBSERVED ANOTHER ACFT ON WHAT APPEARED TO BE A COLLISION COURSE XING FROM L TO R IN THE TFC PATTERN. I IMMEDIATELY TOOK CTL OF THE ACFT AND INITIATED A HARD L CLBING TURN TO AVOID THE ACFT. I RECOGNIZED THE ACFT AS ONE FLOWN BY X; BUT DID NOT SEE THE OTHER ACFT TAKE ANY EVASIVE ACTION. THE CAP [CIVIL AIR PATROL] HAD BEEN FLYING 2 C172 ACFT FROM THE KERRVILLE SCHREINER ARPT ON FRIDAY AND SATURDAY; POSSIBLY ON A PRACTICE SEARCH MISSION. THERE WAS NO NOTICE POSTED AT KERRVILLE ARPT INDICATING ANY INCREASE IN CAP ACTIVITY. I RECOMMEND THAT CAP PROCS BE AMENDED TO REQUIRE NOTAMS BE POSTED FOR ANY PRACTICE SEARCH MISSIONS OR TIMES OF INCREASED FLT ACTIVITY BY THE CAP. THE ARPTS IN THE AREAS AFFECTED BY THE FLT ACTIVITY SHOULD POST NOTICES PROVIDED BY THE CAP INDICATING TIMES; ALTS AND LOCATION OF SEARCH ACTIVITIES SO LCL AIRMEN ARE AWARE OF THE INCREASED FLT ACTIVITY. MAY/FRI/02; ON RETURNING TO KERRVILLE ARPT FOLLOWING A TRAINING FLT; I WAS UNABLE TO MAKE NORMAL RADIO XMISSIONS ON CTAF BECAUSE CAP GND AND FLT PERSONNEL WERE TRYING TO RESOLVE AN FM RADIO COM PROB ON 122.7 (CTAF). CAP NEEDS TO IMPROVE THEIR OPERATING PROCS SO AS NOT TO CREATE A SAFETY OF FLT ISSUE BY CLUTTERING UP CTAF WITH MAINT/OPS TROUBLESHOOTING.