SMA BACK TAXI ON RWY FORCES GAR OF TWIN ON FINAL.

Narrative

DURING PREFLT; AND AS I TAXIED FROM THE RAMP TOWARDS THE RWY; I REALIZED THAT THE ARPT WAS BUSY; AND GETTING BUSIER. I TAXIED TO THE E RUN-UP AREA TO ALLOW A TAILDRAGGER; WHICH WAS TAXIING ON RWY 9; TO TAXI TOWARDS THE RAMP. I CAME TO A FULL STOP IN THE RUN-UP AREA TO WAIT FOR THE TAILDRAGGER AND TO ALLOW IT TO EXIT THE RWY. BACK ON THE RAMP; AN SMA B AND AN SMA C WERE WAITING FOR THE TAILDRAGGER TO CLR THE TAXIWAY. I WAS STILL IN THE RUN-UP AREA; AWARE OF THESE ACFT BEHIND ME; BUT WAS MORE CONCERNED WITH THE TFC IN THE PATTERN. I SAW AND HEARD (ON THE RADIO) AN SMA D ON FINAL FOR 9; AND I HAD SEEN A TWIN IN THE PATTERN DURING MY PREFLT. I NEITHER SAW NOR HEARD THE TWIN NOW. MY PLAN WAS TO WAIT UNTIL THE SMA D COMPLETED ITS TOUCH AND GO; PERFORM MY CLRING TURN; ANNOUNCE MY INTENTION TO BACK-TAXI RWY 9; BACK-TAXI TO THE RUN-UP AREA AT THE W END OF 9; AND PERFORM MY RUN-UP THERE. AS THE SMA D LIFTED OFF; THE SMA B BRAZENLY TAXIED PAST ME AND BEGAN BACK-TAXIING 9. ONLY THEN DID HE ANNOUNCE THAT HE WAS BACK-TAXIING. THIS ANGERED ME SOMEWHAT; SINCE I THINK THAT HE SHOULD HAVE 1) WAITED HIS TURN BEHIND ME; AND 2) ANNOUNCED HIS INTENTIONS FIRST. A BIT DISTRACTED; I MADE MY CLRING TURN; I SAW THE SMA D CLBING OUT; AND I PROCEEDED APPROX 100 YARDS BEHIND THE SMA B. ABOUT HALFWAY TO THE MID-FIELD TURN-OFF; I HEARD THE TWIN ANNOUNCE THAT HE WAS ON A L BASE FOR 9. I WAS VERY SURPRISED; AS I BELIEVED HE WAS NO LONGER IN THE PATTERN. I HAD NOT SEEN HIM DURING THE CLRING TURN; NOR DID I HEAR ANY POS RPTS FROM HIM ON CTAF/UNICOM. HE WAS WELL INTO THE BASE LEG; AND WOULD BE TURNING FINAL SOON. I KNEW THAT I NEEDED TO DECIDE WHETHER TO CONTINUE TAXIING TOWARDS THE MID-FIELD TURN-OFF; TAXI ONTO THE VERY MOIST AND SOFT GND TO MY R; OR TURN AROUND AND TAXI BACK THE ON E RUN-UP AREA. I KNEW THAT THE SMA C WAS BEHIND ME SOMEWHERE SO I DECIDED TO PROCEED FORWARD TO THE MID-FIELD TURN-OFF; AS THE SMA B WAS DOING. THE TWIN WAS NOW ON SHORT FINAL; THE SMA B WAS TURNING OFF AT MID-FIELD; AND I WAS STILL ABOUT 100 YARDS BEHIND THE SMA B. I REALIZED THAT I HAD PROBABLY FORCED THE TWIN INTO A GAR. I PREPARED TO TAXI ONTO THE SOFT GND ON THE R SIDE OF THE RWY IF HE DID NOT GAR. HE BEGAN THE GAR AT ABOUT THE SAME TIME THAT I PULLED INTO THE TURN-OFF AREA. THE SITUATION WAS RESOLVED AT THIS POINT; THANKS TO THE ALERT TWIN PLT. IN ORDER TO PREVENT A RECURRENCE; I SHOULD WORK TOWARDS IMPROVING MY SCAN DURING CLRING TURNS. I DID NOT EXPECT TO SEE THE TWIN AND THIS PROBABLY EXPLAINS WHY I DIDN'T SEE HIM. ANOTHER THING WHICH I SHOULD HAVE DONE AFTER THE SMA B CUT IN FRONT OF ME WAS TO REMAIN IN THE RUN-UP AREA AND REASSESS THE SITUATION. WHEN I SAW HIM TAXI PAST ME; I LET MYSELF GET 'LURED' IN BEHIND HIM. EVEN THOUGH I MADE THE CLRING TURN FIRST; I DIDN'T SEE THE TWIN AND I FOLLOWED THE SMA B INTO A POTENTIALLY DANGEROUS SITUATION. FINALLY; EXTRA VIGILANCE WAS CLRLY CALLED FOR. THE ARPT WAS BUSY; AND I KNEW IT. THIS SITUATION DEMONSTRATES HOW IMPORTANT IT IS TO EXPECT THE UNEXPECTED.