INSTRUCTOR PLT GIVING A CHKOUT IN A C172 TO A PVT PLT TOOK THE ACFT CTLS ON INITIAL CLB; AFTER TKOF FROM AN UNCTLED ARPT TO MAKE AN EVASIVE TURN AWAY FROM A PIPER ARCHER TURNING FINAL TO LAND FROM THE OPPOSITE DIRECTION.

Narrative

I EXPERIENCED AN NMAC ON APR/XA/99 AT APPROX XX50 LCL TIME. I (CFII; MEI) WAS CONDUCTING A C172 CHKOUT FLT FOR A 55 HR PVT PLT. THE FLT ORIGINATED AT MY HOME BASE OF RNH ARPT; WI. WIND CONDITIONS AT THE TIME OF THE NMAC AS RPTED BY THE AUTOMATED WX STATION AT THE ARPT WERE 120 DEGS AT 11 KTS. RWY 14 WAS ASSUMED TO BE THE ACTIVE RWY. RNH IS SERVED BY 2 RWYS; RWY 14/32 (4000 FT PAVED) AND RWY 4/22 (2100 FT TURF). WE TAXIED FROM THE HANGAR AREA; ACROSS THE APRON; AND BACK-TAXIED TO RWY 14. A RUNUP WAS PERFORMED AT THE TURNAROUND AREA NEAR THE THRESHOLD OF RWY 14. AN ANNOUNCEMENT WAS MADE ON THE CTAF (122.9) WE WERE DEPARTING RWY 14 WITH A SE DEP. NO OTHER ACFT WERE RPTING ON THE CTAF. WE TAXIED ONTO RWY 14 AFTER CHKING THE RWY 14 FINAL APCH PATH FOR TFC. WE INITIATED A TKOF; THE PVT PLT IN THE L SEAT WAS AT THE CTLS. AT APPROX 300 FT AGL ON CLBOUT; I NOTICED A PIPER ARCHER ON A CLOSE IN L BASE FOR RWY 32. THE ARCHER WAS SLIGHTLY ABOVE OUR ALT; BUT IN A DSCNT. THE ARCHER WAS IN THE PROCESS OF TURNING FINAL FOR RWY 32 APPROX 1500 FT IN FRONT OF US. I TOOK CTL OF THE ACFT AND MADE A 45 DEG BANK TO THE L. THE ARCHER PASSED TO OUR R AND SLIGHTLY BELOW US AND DID NOT APPEAR TO SEE US. WE PASSED CLOSE ENOUGH TO SEE THE OCCUPANTS OF THE ARCHER AS WELL AS THE N-NUMBER. I SAW NO DEV IN THEIR FLT PATH AND HEARD NO RADIO CALLS DURING OUR FLT OR DURING OUR PRE TKOF ACTIVITIES. I RECOGNIZED THE ACFT. I BELIEVE THE ACFT BELONGS TO A CLUB BASED AT AN ARPT ABOUT 15 MI TO THE SW. WE ENTERED THE TFC PATTERN FOR RWY 14. I NOTICED THE ARCHER LANDED ON RWY 32 WITH A TAILWIND; AND WAS NOW BACK-TAXIING TO THE APRON. I CALLED THE ARCHER ON 122.9 WITH NO REPLY. I TUNED IN 122.8 (THE FREQ AT THE NEARBY ARPT) AND TRIED GIVING THE ARCHER ANOTHER CALL. THEY RESPONDED ON 122.8. I POLITELY INFORMED THEM THE RNH CTAF WAS 122.9 AND WE NEARLY HAD A MIDAIR COLLISION. THEY RESPONDED WITH 'THANK YOU.' I WAS TAKEN COMPLETELY OFF GUARD BY THIS INCIDENT. THE ARCHER WAS IN OUR FIELD OF VIEW FOR ONLY A FEW SECONDS. THE HIGH WING AND THE LARGE STRUT OF THE CESSNA PREVENTED US FROM SEEING THE DSNDING ACFT. THE PVT PLT OCCUPYING THE L SEAT NEVER DID SEE THE ACFT UNTIL IT WAS BACK-TAXIING ON THE RWY. THE LOW ALTS INVOLVED DID NOT ALLOW FOR MANY OPTIONS IN THIS SIT. PROPER RADIO PROCS; PROPER TFC PATTERNS; AND INVISIBLE WINGS ON THE C172 WOULD HAVE HELPED TREMENDOUSLY. THIS INCIDENT WAS A BIT TOO CLOSE FOR ME. AS MGR AT RNH; THE NMAC IS GIVING ME SECOND THOUGHTS ABOUT CHANGING OUR CTAF -- SCHEDULED FOR SEP/XA/99.