Narrative:

My student of approximately 8 hours performed the preflight on our C172 before we started the motor. I questioned him about our fuel, oil, and any maintenance squawks. Confident in my student's ability to preflight the aircraft, we continued through the appropriate checklists. We were cleared to taxi to runway 15 and we performed our runup. Everything was normal, so we taxied to the hold short line. We were cleared for takeoff and out on the runway we went. The wind was from the southwest at 17 KTS, so there was a substantial crosswind. As my student lifted off, I pointed out our drift and instructed him into a crab angle. During this time, my student had lowered the nose to see the ground better, so we essentially flew level for about 1/2 the runway length. I told him to pitch up for vy and to get that climb going. He reacted and pitched up for a vy climb. As we cleared the south field boundary at approximately 300 ft, our RPM decreased steadily and quickly to idle. Unsure of what had happened, I told my student to 'get that power in there!' when he told me it was, I took control of the aircraft and lowered the nose. I initiated a left turn and contacted renton tower to advise them of our emergency. I performed a flow check including the fuel selector -- both, flaps -- up, mixture -- rich, carburetor heat -- on, magnetos -- both, master -- on, primer -- locked. It was apparent that we would not make it back to the airport, so I advised the tower and headed for a parking lot 1/4 mi east of the airport. As I approached my intended point of landing, I decided it would be better to continue to the road, just east of the parking lot. The traffic on the road was at a stop light I was about to pass over. As we were about to clear a row of trees, I instructed my student to open his door and brace himself. Lucky for us, we made it over the trees and leveled out over the road. There was 1 power line crossing the road, so we went under it and touched down. With maximum braking we came to a stop just through an intersection without hitting anything and without any damage. I then advised the tower that we were safe and we then secured the aircraft. (Mixture -- cutoff, magnetos -- off, master switch -- off). By this time, emergency crews were on the scene and we were evaluating the aircraft. With the help of some on-lookers, we pushed the aircraft back to the airport. An inspection was performed the next morning that revealed a piece of sealant from the carburetor drain plug had detached and blocked the fuel nozzle, restricting the flow of fuel. Because the idle circuit was not plugged, the engine continued to run at idle only. The aircraft as well as myself were flying the next afternoon.

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Original NASA ASRS Text

Title: C172 INSTRUCTOR AND TRAINEE HAD FORCED LNDG, OFF ARPT.

Narrative: MY STUDENT OF APPROX 8 HRS PERFORMED THE PREFLT ON OUR C172 BEFORE WE STARTED THE MOTOR. I QUESTIONED HIM ABOUT OUR FUEL, OIL, AND ANY MAINT SQUAWKS. CONFIDENT IN MY STUDENT'S ABILITY TO PREFLT THE ACFT, WE CONTINUED THROUGH THE APPROPRIATE CHKLISTS. WE WERE CLRED TO TAXI TO RWY 15 AND WE PERFORMED OUR RUNUP. EVERYTHING WAS NORMAL, SO WE TAXIED TO THE HOLD SHORT LINE. WE WERE CLRED FOR TKOF AND OUT ON THE RWY WE WENT. THE WIND WAS FROM THE SW AT 17 KTS, SO THERE WAS A SUBSTANTIAL XWIND. AS MY STUDENT LIFTED OFF, I POINTED OUT OUR DRIFT AND INSTRUCTED HIM INTO A CRAB ANGLE. DURING THIS TIME, MY STUDENT HAD LOWERED THE NOSE TO SEE THE GND BETTER, SO WE ESSENTIALLY FLEW LEVEL FOR ABOUT 1/2 THE RWY LENGTH. I TOLD HIM TO PITCH UP FOR VY AND TO GET THAT CLB GOING. HE REACTED AND PITCHED UP FOR A VY CLB. AS WE CLRED THE S FIELD BOUNDARY AT APPROX 300 FT, OUR RPM DECREASED STEADILY AND QUICKLY TO IDLE. UNSURE OF WHAT HAD HAPPENED, I TOLD MY STUDENT TO 'GET THAT PWR IN THERE!' WHEN HE TOLD ME IT WAS, I TOOK CTL OF THE ACFT AND LOWERED THE NOSE. I INITIATED A L TURN AND CONTACTED RENTON TWR TO ADVISE THEM OF OUR EMER. I PERFORMED A FLOW CHK INCLUDING THE FUEL SELECTOR -- BOTH, FLAPS -- UP, MIXTURE -- RICH, CARB HEAT -- ON, MAGNETOS -- BOTH, MASTER -- ON, PRIMER -- LOCKED. IT WAS APPARENT THAT WE WOULD NOT MAKE IT BACK TO THE ARPT, SO I ADVISED THE TWR AND HEADED FOR A PARKING LOT 1/4 MI E OF THE ARPT. AS I APCHED MY INTENDED POINT OF LNDG, I DECIDED IT WOULD BE BETTER TO CONTINUE TO THE ROAD, JUST E OF THE PARKING LOT. THE TFC ON THE ROAD WAS AT A STOP LIGHT I WAS ABOUT TO PASS OVER. AS WE WERE ABOUT TO CLR A ROW OF TREES, I INSTRUCTED MY STUDENT TO OPEN HIS DOOR AND BRACE HIMSELF. LUCKY FOR US, WE MADE IT OVER THE TREES AND LEVELED OUT OVER THE ROAD. THERE WAS 1 PWR LINE XING THE ROAD, SO WE WENT UNDER IT AND TOUCHED DOWN. WITH MAX BRAKING WE CAME TO A STOP JUST THROUGH AN INTXN WITHOUT HITTING ANYTHING AND WITHOUT ANY DAMAGE. I THEN ADVISED THE TWR THAT WE WERE SAFE AND WE THEN SECURED THE ACFT. (MIXTURE -- CUTOFF, MAGNETOS -- OFF, MASTER SWITCH -- OFF). BY THIS TIME, EMER CREWS WERE ON THE SCENE AND WE WERE EVALUATING THE ACFT. WITH THE HELP OF SOME ON-LOOKERS, WE PUSHED THE ACFT BACK TO THE ARPT. AN INSPECTION WAS PERFORMED THE NEXT MORNING THAT REVEALED A PIECE OF SEALANT FROM THE CARB DRAIN PLUG HAD DETACHED AND BLOCKED THE FUEL NOZZLE, RESTRICTING THE FLOW OF FUEL. BECAUSE THE IDLE CIRCUIT WAS NOT PLUGGED, THE ENG CONTINUED TO RUN AT IDLE ONLY. THE ACFT AS WELL AS MYSELF WERE FLYING THE NEXT AFTERNOON.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.