A C172 PLT TAXIED ONTO THE RWY OF A NON TWR ARPT ASSUMING HE HAD ENOUGH ROOM AND TIME TO DEPART BEFORE LNDG TFC.

Narrative

WE (MY STUDENT AND I) WERE HOLDING SHORT OF RWY 8 AT 1V5. WE WERE NEXT IN LINE TO TAKE OFF; A BELLANCA VIKING WAS WAITING BEHIND US. AN EDGE 540 WAS IN THE DOWNWIND ABEAM THE NUMBER 8. WE NORMALLY CAN DEPART RWY 8 WITH ACFT ON THE DOWNWIND (BECAUSE IT TAKES TIME TO GET TO BASE AND SO ON). THE EDGE 540 APPARENTLY DECIDED TO MAKE A SHORT APCH (NOTHING WAS SAID FROM THE EDGE 540 ABOUT HIS INTENTIONS). WE ANNOUNCED OUR TAXI ONTO THE RWY. AT THAT POINT THE EDGE 540 ANNOUNCED THAT HE WAS SHORT FINAL (HE WAS ACTUALLY ON BASE) AND TOLD US TO GET OFF THE RWY. WE IMMEDIATELY TURNED BACK TOWARDS THE TXWY. AT THIS POINT; THE BELLANCA VIKING PULLED TO THE HOLD SHORT LINE EFFECTIVELY TRAPPING US ON THE RWY. I TURNED THE AIRPLANE TO SEE THE APCHING EDGE 540. THE PLT OF THE EDGE 540 THEN TOLD US TO HOLD OUR POS; HE WOULD LAND PAST US. HE CHOSE TO LAND RIGHT OVER US INSTEAD OF EXTENDING THE LNDG SOMEWHAT. HE MISSED US BY 15-20 FT OR SO. HE MAY HAVE BEEN EXPERIENCED ENOUGH TO FEEL COMFORTABLE MISSING US BY SUCH A SHORT AMOUNT BUT I DID NOT. WE SUBSEQUENTLY TOOK OFF FOR THE FLT.