GEAR UP LNDG.

Narrative

A STUDENT AND I WERE ON OUR WAY BACK TO THE ARPT AFTER PRACTICING SINGLE ENG PROCS. WE WERE AT 4200 FT AGL AND I ASKED THE STUDENT TO STAY AT THAT ALT AND SPIRAL DONE OVER THE NUMBERS 17 WHICH WAS THE ACTIVE RWY. THE SPIRAL WAS ENTERED AND 3 TURNS WERE ACCOMPLISHED. AT 1500 FT AGL WE PULLED OUT OF THE SPIRAL NBOUND TO TURN BASE AND FINAL. DURING THIS WHOLE MANEUVER THE THROTTLES WERE SET AT IDLE. UPON TURNING FINAL THE STUDENT REALIZED WE WERE A LITTLE LOW AND ELECTED TO LEAVE THE GEAR UP TO EXTEND OUR GLIDE; WHICH I FELT WAS OK. AT ABOUT 100 FT AGL THE GEAR LEVER WAS PUSHED DOWN TO EXTEND THE GEAR. I REALIZED WE WERE A LITTLE LOW AND CONCENTRATED ON THE STUDENT GETTING THE PLANE OVER A FENCE BY ADDING PWR AND LEVELING THE PITCH. WHEN IT WAS TIME TO FLARE I NOTICED THE ACFT WAS LOWER THAN USUAL. I FELT THE WHEELS TOUCH DOWN BUT THE ACFT JUST KEPT SINKING UNTIL METAL STARTED TO SCRAPE. AT THIS POINT I TOOK THE PLANE AND PULLED BACK ON THE YOKE TO KEEP THE NOSE FROM SKIPPING ON THE PAVEMENT AND PULLED THE MIXTURES BACK TO IDLE CUT-OFF. WHEN WE CAME TO A STOP I TURNED THE FUEL OFF; TURNED THE MASTER OFF AND TRIED TO GET TO THE MAGS BUT WAS UNABLE BECAUSE THEY ARE ON THE STUDENTS L SIDE. I GRABBED THE STUDENT BY THE ARM AND EVACUATED.