INFLT ENG SHUTDOWN - WHILE PRACTICING ENG OUT APCHS THE ENG QUIT AND THE PLTS LANDED OFF ARPT.

Narrative

AS PART OF THE PRIMARY STUDENT TRAINING; I AS A CFI AM REQUIRED TO PREPARE THE STUDENT FOR EMER SITS. PART OF THIS TRAINING INVOLVES REDUCING PWR AND SETTING UP FOR AN EMER LNDG. ON THE DAY OF THIS INCIDENT THE C-150 WE WERE USING HAD BEEN FLOWN OVER 4 HRS WITH NO PROBS. ON THE LAST FLT OF THE DAY I HAD A STUDENT WHO IS PREPARING FOR HIS PVT PLT CHK RIDE. WE STARTED THE TRAINING SESSION WITH TURNS AROUND A POINT. DURING THIS PHASE I CHOPPED PWR AND HAD THE STUDENT SET UP FOR AN EMER. THERE WAS A GRASS STRIP NEARBY AND WE SET UP FOR A NORMAL PWR OFF LNDG. THIS WENT WITHOUT EVENT. WE MADE A LOW PASS; AT WHICH TIME I APPLIED FULL PWR WITH NO PROBS. NEXT WE WERE CLBING OUT AND AFTER SEVERAL MINS AT PWR I APPLIED CARB HEAT AND AGAIN CUT PWR. A GOOD FIELD WAS SELECTED AND WE WERE ON THE DOWNWIND LEG WHEN PWR WAS CUT. WE MADE A R DOWNWIND AND BASE IN SETTING UP FOR THE LNDG. AT ROUGHLY 300 FT AGL; I ORDERED PWR. WHEN THE STUDENT APPLIED THROTTLE THERE WAS A TOTAL LOSS OF PWR. FORTUNATELY; WE HAD SET UP PROPERLY AND HAD A PLACE TO LAND. SUBSEQUENTLY; WE WENT THROUGH THE CHKLIST (MENTALLY) AND LANDED THE PLANE WITH NO PROBS. ONCE ON THE GND WE TRIED TO RESTART TO NO AVAIL. NEXT WE FOUND A LOCAL A AND E WHO SAW NOTHING WRONG. AGAIN WE TRIED TO RESTART AND IT STARTED FINE (20-30 MINS LATER). AFTER RUN-UP AND CHKOUT I WAS ABLE TO TKOF AGAIN AND RETURN SAFELY. THE ONLY EXPLANATION CAN BE CARB ICING. WHEN I GOT BACK TO MFV I CHKED THE TEMP/DEW POINT AND FOUND THE SPREAD TO BE 51 DEGS/26 DEGS (VERY DRY AIR). ANY TIME WE REDUCE PWR; CARB HEAT IS APPLIED. ON RUN-UP WE NORMALLY GET A 75-100 RPM DROP. WE HAD BEEN RUNNING AT FULL PWR AT THE TIME OF THE INCIDENT. SUBSEQUENTLY; (THE NEXT DAY) THE AIRPLANE WAS DELIVERED TO THE REGULAR MECH FOR A COMPLETE INSPECTION. MORAL OF THE STORY - ALWAYS HAVE A GOOD SITE CHOSEN FOR PRACTICE EMERS. STAY CALM AND BE READY TO PERFORM THE PROCS. IN THIS CASE THERE WERE NO INJURIES OR DAMAGES.