CITABRIA PLT ON FINAL AT A BUSY NON-TOWERED AIRPORT; EXECUTES A GO-AROUND WHEN A DECATHALON IS NOTICED OCCUPYING THE RUNWAY.

Narrative

WHILE APCHING THE NUMBERS ON VERY SHORT FINAL AT ZZZ IN THE CITABRIA; A DECATHLON MOVED FROM A HOLD SHORT POS ONTO THE RWY. AS THE CITABRIA PASSED DIRECTLY OVER THE DECATHLON I ANNOUNCED ON THE CTAF; 'DECATHLON ON THE RWY THE CITABRIA IS DIRECTLY OVERHEAD;' I HEARD A RESPONSE OF; 'THAT'S NOT GOOD BETTER GO AROUND.' I IMMEDIATELY ABORTED THE LNDG AND EXECUTED A GAR. ABOUT MIDFIELD 300 FT AGL I WAS SURPRISED AS THE DECATHLON CLBED IN FRONT OF THE CITABRIA APPROX 30 FT AWAY. I FOLLOWED THE DECATHLON ON THE UPWIND AND XWIND LEGS CALLING THEM ON THE RADIO WITH NO RESPONSE. THE DECATHLON DEPARTED THE PATTERN ON THE XWIND LEG. I PROCEEDED ON THE DOWNWIND LEG LNDG ON RWY 18 WITHOUT FURTHER INCIDENT. TFC: THE TFC PATTERN AND GND TFC AT THE ARPT WAS RELATIVELY BUSY AS A FLY-IN EVENT WAS IN PROGRESS. ANNOUNCEMENTS ON THE CTAF WERE ACTIVE; COOPERATIVE; AND ALL TFC HAD ADEQUATE SEPARATION. THE CITABRIA WAS FOLLOWED IN THE PATTERN BY 2 OTHER ACFT. #2 BEHIND THE CITABRIA WAS A PIPER J3 CUB ALSO ON FINAL. DISCUSSIONS ON THE GND: THE DECATHLON PLT (WHO RETURNED TO THE ARPT SHORTLY AFTER THE INCIDENT) TOLD ME THAT HE NEVER SAW THE CITABRIA IN THE PATTERN ALTHOUGH HE DID SEE THE CUB. HE ALSO TOLD ME HE NEVER HEARD ANY OF MY CALLS AS HE WAS 'JABBERING TO HIS PAX;' 'NOT PAYING ATTN;' AND THAT HE 'WOULD NEVER DO THAT AGAIN; LESSON LEARNED.' I LEARNED FROM THE CUB PLT THAT HE ANSWERED THE CALL I MADE TO THE DECATHLON AS THE CITABRIA WAS DIRECTLY OVERHEAD. PERCEPTIONS/DECISIONS/ACTIONS: WHEN I HEARD THE CUB PLT RESPOND TO MY CALL WHILE OVER THE DECATHLON; MY PERCEPTION WAS THAT THE DECATHLON PLT WAS RESPONDING TO MY CALL; SAW ME; AND WOULD NOT BEGIN A TKOF ROLL. IN HINDSIGHT; AS THE DECATHLON PLT NEVER SAW ME IN THE PATTERN BEFORE OR AFTER THE NEAR-MISS; A MORE AGGRESSIVE CLB MIGHT HAVE ALLOWED FOR MORE SEPARATION BTWN OUR ACFT. THE CITABRIA HAS A 115 HP ENG; AND THE DECATHLON A 180 HP ENG ALLOWING FOR A FASTER CLB RATE. IN HINDSIGHT; A TURN WOULD HAVE MOVED ME OUT OF THE DECATHLON'S PATH. IT WOULD HAVE BEEN VERY HELPFUL IF THE CUB PLT ADVISED OF THE DECATHLON'S TKOF ROLL AND/OR CLB TOWARDS THE CITABRIA (THE DECATHLON PLT DID NOT USE HIS RADIO WHILE TAXIING ONTO THE RWY; ON TKOF ROLL; OR IN THE PATTERN). ALL DISCUSSIONS BTWN THE PLTS AND OTHER OBSERVERS ON THE GND WERE PROFESSIONAL AND IN THE INTEREST OF SAFETY AND EDUCATION.