Narrative:

At approximately XA00Z on feb/xa/00, I experienced complete loss of engine power while giving dual instruction in a C172. We were at 4500 ft MSL (approximately 3000 ft AGL) over a reservoir in a power-off stall with carburetor heat applied. I immediately took the controls from my student, established vg/best glide for the aircraft, troubleshot, contacted 121.5, squawked 7700, and glided in the direction of a gravel strip. The aircraft never regained power. This was my second day as a flight instructor. Ironically, the previous day, I had simulated an engine failure with another student over the same reservoir to the vicinity of the gravel strip. We came in at least 1500 ft high of the strip. I elected to execute a 360 degree turn for spacing. On final approach, both my student and I determined that we would glide short of the strip and landed without difficulty on a closer field. My student and I suffered no injuries and the plane was not damaged. The aircraft was later pulled from the field to the strip and flown back to its home airport after an inspection by an authority/authorized a&P mechanic who determined the cause to be carburetor icing. My prior flight experience in C172's had been in aircraft with lycoming engines. The aircraft I was flying that day had a continental engine. A mechanic at the airport informed me that continental engines are more susceptible to carburetor icing than lycoming's because a lycoming's carburetor is externally assisted by the warmth of the nearby oil sump. Although I was operating the aircraft in a manner consistent with my training, the experience proved invaluable to myself, my students (present and future), and all of the pilots with whom I have contact as they may someday encounter similar sits with continental-equipped airplanes.

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Original NASA ASRS Text

Title: C172 ENG QUIT DURING PWR-OFF STALL PRACTICE RESULTING IN AN ACTUAL OFF ARPT FORCED LNDG. NO INJURIES OF ACFT DAMAGE.

Narrative: AT APPROX XA00Z ON FEB/XA/00, I EXPERIENCED COMPLETE LOSS OF ENG PWR WHILE GIVING DUAL INSTRUCTION IN A C172. WE WERE AT 4500 FT MSL (APPROX 3000 FT AGL) OVER A RESERVOIR IN A PWR-OFF STALL WITH CARB HEAT APPLIED. I IMMEDIATELY TOOK THE CTLS FROM MY STUDENT, ESTABLISHED VG/BEST GLIDE FOR THE ACFT, TROUBLESHOT, CONTACTED 121.5, SQUAWKED 7700, AND GLIDED IN THE DIRECTION OF A GRAVEL STRIP. THE ACFT NEVER REGAINED PWR. THIS WAS MY SECOND DAY AS A FLT INSTRUCTOR. IRONICALLY, THE PREVIOUS DAY, I HAD SIMULATED AN ENG FAILURE WITH ANOTHER STUDENT OVER THE SAME RESERVOIR TO THE VICINITY OF THE GRAVEL STRIP. WE CAME IN AT LEAST 1500 FT HIGH OF THE STRIP. I ELECTED TO EXECUTE A 360 DEG TURN FOR SPACING. ON FINAL APCH, BOTH MY STUDENT AND I DETERMINED THAT WE WOULD GLIDE SHORT OF THE STRIP AND LANDED WITHOUT DIFFICULTY ON A CLOSER FIELD. MY STUDENT AND I SUFFERED NO INJURIES AND THE PLANE WAS NOT DAMAGED. THE ACFT WAS LATER PULLED FROM THE FIELD TO THE STRIP AND FLOWN BACK TO ITS HOME ARPT AFTER AN INSPECTION BY AN AUTH A&P MECH WHO DETERMINED THE CAUSE TO BE CARB ICING. MY PRIOR FLT EXPERIENCE IN C172'S HAD BEEN IN ACFT WITH LYCOMING ENGS. THE ACFT I WAS FLYING THAT DAY HAD A CONTINENTAL ENG. A MECH AT THE ARPT INFORMED ME THAT CONTINENTAL ENGS ARE MORE SUSCEPTIBLE TO CARB ICING THAN LYCOMING'S BECAUSE A LYCOMING'S CARB IS EXTERNALLY ASSISTED BY THE WARMTH OF THE NEARBY OIL SUMP. ALTHOUGH I WAS OPERATING THE ACFT IN A MANNER CONSISTENT WITH MY TRAINING, THE EXPERIENCE PROVED INVALUABLE TO MYSELF, MY STUDENTS (PRESENT AND FUTURE), AND ALL OF THE PLTS WITH WHOM I HAVE CONTACT AS THEY MAY SOMEDAY ENCOUNTER SIMILAR SITS WITH CONTINENTAL-EQUIPPED AIRPLANES.

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.