Narrative:

I was on an instructional flight with a student and upon returning to the airport, we planned to do a touch and go followed by a full stop. The student was in control while taking off from the touch and go when I noticed a hesitation in the engine. I immediately took control of the aircraft and announced 'my controls.' student relinquished controls and I think, assumed he had done something wrong. I immediately thereafter, added full mixture and turned on carburetor heat which initially seemed to work and power was restored. Based on the fact that I thought power was restored I called tower, notified them I had engine trouble and turned right onto crosswind for runway 24R. Tower cleared me to land anywhere necessary and I advised them I would land runway 15. I was cleared to land runway 15. While turning from what was (right) crosswind for runway 24R to what was now right base for runway 15 the engine again quit, this time completely. I pitched for best glide and prepared my student for an emergency landing. I think my student was unaware for the most part that this was an actual emergency and not a training exercise. The plane landed just short of the runway and came to a stop on the runway. Neither myself, the student, the plane, or anything else suffered any damage. The plane was then towed to the hangar and was started up by the mechanic. The problem could have been carburetor ice, as it was an unusually humid day for arizona. The low fuel quantity also could have been a factor which is what I suspect. The cessna 150 has small tanks and may have had interruption of fuel flow either due to moisture or sloshing of fuel. I later discussed the events with my student and explained that although things turned out, a better choice may have been to select a landing area straight ahead.

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Original NASA ASRS Text

Title: A C150 HAS AN ENG FAILURE AFTER TKOF RESULTING IN LNDG JUST SHORT OF THE RWY.

Narrative: I WAS ON AN INSTRUCTIONAL FLT WITH A STUDENT AND UPON RETURNING TO THE ARPT, WE PLANNED TO DO A TOUCH AND GO FOLLOWED BY A FULL STOP. THE STUDENT WAS IN CTL WHILE TAKING OFF FROM THE TOUCH AND GO WHEN I NOTICED A HESITATION IN THE ENG. I IMMEDIATELY TOOK CTL OF THE ACFT AND ANNOUNCED 'MY CTLS.' STUDENT RELINQUISHED CTLS AND I THINK, ASSUMED HE HAD DONE SOMETHING WRONG. I IMMEDIATELY THEREAFTER, ADDED FULL MIXTURE AND TURNED ON CARB HEAT WHICH INITIALLY SEEMED TO WORK AND PWR WAS RESTORED. BASED ON THE FACT THAT I THOUGHT PWR WAS RESTORED I CALLED TWR, NOTIFIED THEM I HAD ENG TROUBLE AND TURNED R ONTO XWIND FOR RWY 24R. TWR CLRED ME TO LAND ANYWHERE NECESSARY AND I ADVISED THEM I WOULD LAND RWY 15. I WAS CLRED TO LAND RWY 15. WHILE TURNING FROM WHAT WAS (R) XWIND FOR RWY 24R TO WHAT WAS NOW R BASE FOR RWY 15 THE ENG AGAIN QUIT, THIS TIME COMPLETELY. I PITCHED FOR BEST GLIDE AND PREPARED MY STUDENT FOR AN EMER LNDG. I THINK MY STUDENT WAS UNAWARE FOR THE MOST PART THAT THIS WAS AN ACTUAL EMER AND NOT A TRAINING EXERCISE. THE PLANE LANDED JUST SHORT OF THE RWY AND CAME TO A STOP ON THE RWY. NEITHER MYSELF, THE STUDENT, THE PLANE, OR ANYTHING ELSE SUFFERED ANY DAMAGE. THE PLANE WAS THEN TOWED TO THE HANGAR AND WAS STARTED UP BY THE MECH. THE PROB COULD HAVE BEEN CARB ICE, AS IT WAS AN UNUSUALLY HUMID DAY FOR ARIZONA. THE LOW FUEL QUANTITY ALSO COULD HAVE BEEN A FACTOR WHICH IS WHAT I SUSPECT. THE CESSNA 150 HAS SMALL TANKS AND MAY HAVE HAD INTERRUPTION OF FUEL FLOW EITHER DUE TO MOISTURE OR SLOSHING OF FUEL. I LATER DISCUSSED THE EVENTS WITH MY STUDENT AND EXPLAINED THAT ALTHOUGH THINGS TURNED OUT, A BETTER CHOICE MAY HAVE BEEN TO SELECT A LNDG AREA STRAIGHT AHEAD.

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.