C172 PLTS EXPERIENCE NMAC WITH OPPOSITE DIRECTION PA34 AFTER RECEIVING A TCAS TFC ALERT.

Narrative

AFTER COMPLETING PRACTICE OF SINGLE ENG COMMERCIAL MANEUVERS IN THE N PRACTICE AREA LOCATED N OF DAYTONA BEACH INTL WE PROCEEDED TO DSND OUT OF 4000 FT NBOUND TOWARDS FLAGLER COUNTY ARPT (X47). APPROX 3 MI S OF X47; AND DSNDING AT APPROX 200-300 FPM PASSING THROUGH 2500 FT WE RECEIVED AN AURAL AND VISUAL TFC ALERT FROM TCAS. WE OBSERVED TFC ON THE TCAS DISPLAY AT APPROX 300 FT ABOVE AND 2 MI AT OUR 12 O'CLOCK POS. WE CONTINUED OUR SLOW DSCNT AND MAINTAINED A NORTHERLY HEADING TOWARDS X47 AND DIVERTED MOST OF OUR ATTN TO OBTAINING VISUAL CONTACT ON THE TFC. THE NEXT TCAS UPDATE SHOWED THE TFC AT OUR 12 O'CLOCK POS; LESS THAN 1 MI AND ONLY 100 FT ABOVE OUR POS. MY FRIEND WHO IS A PVT SINGLE-; MULTI-ENG COMMERCIAL PLT WITH INST AIRPLANE YELLED OUT AS HE SAW WHAT HE THOUGHT TO BE A JET HEADING STRAIGHT FOR US AT THE SAME ALT. AT THIS POINT I BEGAN TRYING TO MAKE VISUAL CONTACT WITH THE ACFT. APPROX 3 SECONDS AFTER MY FRIEND'S WARNING; I OBSERVED A MULTI-ENG ACFT AT OUR 11-12 O'CLOCK POS AND NEARLY THE SAME ALT. THE SIZE OF THE APCHING ACFT WAS RAPIDLY INCREASING. AFTER A SECOND OR TWO; I COULD TELL THAT THE ACFT WAS A PISTON MULTI-ENG. UPON VISUAL CONTACT; I IMMEDIATELY PUSHED THE YOKE FORWARD AND STARTED A R TURN. THE ACFT CONTINUED AHEAD AND ALSO DEVIATED R AFTER ABOUT ANOTHER 2 SECONDS. WE WERE CLOSE ENOUGH TO SEE THE PIN STRIPES ON THE PASSING SENECA. A MAJOR CONTRIBUTING FACTOR TO THE NMAC WAS THE TCAS WAS ZOOMED IN TOO CLOSE (ON THE 1 MI RANGE) SO THAT WE COULD NOT SEE THE APCHING TFC UNTIL WE RECEIVED THE TFC ALERT. TO RESOLVE THIS; PLTS MUST HAVE THE TCAS DISPLAYED TO AN ACCEPTABLE RANGE TO GIVE AMPLE TIME TO OBSERVE ONCOMING TFC.