RPTR HAS NMAC WITH ANOTHER LNDG ACFT AT ABOUT 100 FT.

Narrative

WHILE ENGAGED IN PRACTICE FOR THE UPCOMING NIFA NATIONAL COMPETITION; MYSELF AND ANOTHER ACFT HAD A NMAC.I WAS THE TRAILING ACFT; AND HAD THE ACFT IN FRONT OF ME IN SIGHT WHILE ON FINAL APCH TO RWY 36. I ASSUMED THAT THE OTHER ACFT WAS MAKING A LOW APCH TO THE MESSAGE DROP TARGETS THAT PARALLEL THE RWY ON THE R SIDE. THE OTHER ACFT PASSED ABOVE AND TO THE R OF ME; AND THE VIEW OF THE OTHER ACFT WAS BLOCKED. I CONTINUED MY APCH UNTIL ABOUT 100 FT AGL; WHEN I SAW GND OBSERVERS WAVING ME OFF. I INITIATED A MISSED APCH AND CLBED OUT. I SAW THE OTHER ACFT BEHIND ME LNDG ON THE RWY. THIS WAS THE FIRST INDICATION I HAD THAT THE OTHER PLANE WAS LNDG. NEITHER ACFT SAW EACH OTHER AT THE POINT OF CLOSEST APCH; BUT GND OBSERVERS ESTIMATED CLOSEST APCH AT 50 FT. PROBABLE CAUSES INCLUDE POOR DECISION MAKING ON MY PART; WITH FAILURE TO KEEP THE OTHER ACFT IN SIGHT AT ALL TIMES THE PRIMARY ERROR. CONTRIBUTING PROBS INCLUDE A MALFUNCTIONING RADIO IN THE OTHER ACFT; WHICH HAMPERED COMS. IN THE FUTURE; BETTER GND BRIEFINGS BEFORE FLT PRACTICE SHOULD PRECLUDE THE NEED FOR FALSE ASSUMPTIONS AND ERRORS.