PLT OF PA28 ENCOUNTERED AN NMAC WITH EXPERIMENTAL ACFT ON FINAL APCH TO GSH. PLT OF EXPERIMENTAL ACFT WAS USING INCORRECT CTAF FREQ FOR POS XMISSIONS.

Narrative

ACFT #1 APCHED THE GOSHEN; IN; ARPT ON AN IFR FLT PLAN IN VMC. ON ESTABLISHING VISUAL CONTACT WITH THE ARPT; THE IFR FLT PLAN WAS CANCELLED WITH ATC AND THE ACFT PROCEEDED TO ENTER THE TFC PATTERN; MAKING POS ANNOUNCEMENTS ON THE CTAF. ANOTHER ACFT (A CESSNA 172); NOT INVOLVED IN THIS INCIDENT; ACKNOWLEDGED ESTABLISHING VISUAL CONTACT WITH ACFT #1 AND VICE VERSA. ACFT #1; AFTER ENSURING ADEQUATE SPACING FROM THE CESSNA; TURNED BASE AND SUBSEQUENTLY FINAL. AT ABOUT 150-200 FT AGL AND APPROX 0.5 NM FROM THE RWY THRESHOLD; THE PLT OF ACFT #1 HEARD A LOUD ENG NOISE FROM THE R SIDE OF THE AIRPLANE AND LOOKED IN THAT DIRECTION; JUST IN TIME TO SEE AN EXPERIMENTAL ACFT PULL AWAY INTO A CLBING R TURN NOT MORE THAN 20 FT FROM ACFT #1 -- CLOSE ENOUGH TO CLRLY SEE THE RIVETS. ACFT #1 LANDED; PARKED CLOSE TO THE C172 AND IN A CONVERSATION WITH THE PLT OF THAT AIRPLANE IT WAS DETERMINED THAT NEITHER OF US HAD HEARD ANY POS ANNOUNCEMENTS FROM THE PLT OF ACFT #2. PRESENTLY THE PLT OF ACFT #2 LANDED; PARKED AND WALKED OVER. THE PLT OF ACFT #1 REMARKED TO HIM THAT HE SEEMED TO HAVE 'COME OUT OF THE BLUE' AND THAT HE SHOULD HAVE MADE POS ANNOUNCEMENTS; AT WHICH POINT HE STATED THAT HE WAS INDEED DOING SO. THE PLT OF THE CESSNA AND THAT OF ACFT #1 BOTH STATED THAT NEITHER HAD HEARD ANY OF HIS ANNOUNCEMENTS; AT WHICH HE REITERATED THAT HE HAD MADE ALL POS ANNOUNCEMENTS. AT THIS POINT; THE PLT OF ACFT #1 REMARKED THAT HE MUST HAVE BEEN USING THE WRONG FREQ. THE PLT OF ACFT #2 THEN SAID THAT HE WAS MAKING ALL ANNOUNCEMENTS ON A FREQ OF 123.0 MHZ. BOTH THE OTHER PLTS STATED THAT THAT WAS THE WRONG FREQ AND THAT HE SHOULD HAVE BEEN USING 123.05. HE STATED THAT IT WAS THE CORRECT FREQ AND; FROM HIS ACFT; PRODUCED A STATE AERONAUTICAL CHART; CLRLY MARKED 'NOT FOR NAV -- WITH 123.0 AS THE CTAF FREQ.' THE PLT OF THE CESSNA AND THAT OF ACFT #1 POINTED THAT OUT TO THE PLT OF ACFT #2; AT WHICH POINT HE STOOD SILENT; WITH A RATHER SHEEPISH LOOK ON HIS FACE.