Narrative:

On the day of the incident, my student and I were practicing lndgs. Once established on final, my student made a slip to landing due to a slightly high approach. After crossing the approach end of the runway, the aircraft was in a slightly fast (at 75-80 KTS), but stabilized leveloff over the runway. At this time, I was stressing the importance of maintaining centerline alignment. We were to the left of centerline so my student made the necessary aileron and rudder inputs to the right to correct. At this time I would estimate our position to be 5-10 ft left of centerline, and at 5 ft above the runway. At that moment (or very shortly thereafter, the aircraft violently began to yaw (more so than roll) and roll to the right, and sink to the runway. As soon as the aircraft began to yaw, I took control of the aircraft and added full power, left rudder, and left aileron. The aircraft struck the runway at least at a 45-60 degree angle (longitudinal axis of the airplane relative to the runway heading) causing damage to the tail and right wingtip (we did not know that we had struck any surface of the aircraft other than the main gear). Although the controls seemed to be fairly ineffective, I eventually was able to get the aircraft aligned with the runway. Although we were aligned with the runway, we were on the far right edge of it. I could see us heading straight for the runway edge identify lights (and many obstacles off of the runway). I knew we were running out of runway and determined that it would be safer to be in the air than on the ground. I noted that my airspeed was 45-50 KTS. At that airspeed, I could handle the airplane better in the air than on the ground. So I applied 10 degrees of flaps, rotated into ground effect, accelerated to 60 KTS, and proceeded to go around. Once the aircraft was airborne and stabilized, I returned for landing. My estimation of the time elapsed between the initial yaw, and the time we got airborne was 5-10 seconds. Synopsis: to the best of my knowledge, we encountered a horizontal windshear. To the best of my understanding, we went from having a straight headwind to a left quartering tailwind. I believe 2 things happened. First, the gust from the left lifted the left wing up. Secondly, the sudden shift from a headwind to a tailwind reduced the effective airflow over the wing and control surfaces at or below staling speeds. Thus the aircraft may have stalled and possibly entered an initial spin. Being so close to the runway, it was impossible to recover from the high rate of sink. I believe that I flew the airplane the best it could be flown for the conditions at hand. Had I not reacted quickly and effectively, the aircraft would most likely have cartwheeled down the runway resulting in the loss of the airplane and possibly our lives.

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Original NASA ASRS Text

Title: A LNDG C152 EXPERIENCES A WINDSHEAR AND LOSS OF ACFT CTL. AFTER A GND STRIKE THE INSTRUCTOR PLT PERFORMS A GAR.

Narrative: ON THE DAY OF THE INCIDENT, MY STUDENT AND I WERE PRACTICING LNDGS. ONCE ESTABLISHED ON FINAL, MY STUDENT MADE A SLIP TO LNDG DUE TO A SLIGHTLY HIGH APCH. AFTER XING THE APCH END OF THE RWY, THE ACFT WAS IN A SLIGHTLY FAST (AT 75-80 KTS), BUT STABILIZED LEVELOFF OVER THE RWY. AT THIS TIME, I WAS STRESSING THE IMPORTANCE OF MAINTAINING CTRLINE ALIGNMENT. WE WERE TO THE L OF CTRLINE SO MY STUDENT MADE THE NECESSARY AILERON AND RUDDER INPUTS TO THE R TO CORRECT. AT THIS TIME I WOULD ESTIMATE OUR POS TO BE 5-10 FT L OF CTRLINE, AND AT 5 FT ABOVE THE RWY. AT THAT MOMENT (OR VERY SHORTLY THEREAFTER, THE ACFT VIOLENTLY BEGAN TO YAW (MORE SO THAN ROLL) AND ROLL TO THE R, AND SINK TO THE RWY. AS SOON AS THE ACFT BEGAN TO YAW, I TOOK CTL OF THE ACFT AND ADDED FULL PWR, L RUDDER, AND L AILERON. THE ACFT STRUCK THE RWY AT LEAST AT A 45-60 DEG ANGLE (LONGITUDINAL AXIS OF THE AIRPLANE RELATIVE TO THE RWY HDG) CAUSING DAMAGE TO THE TAIL AND R WINGTIP (WE DID NOT KNOW THAT WE HAD STRUCK ANY SURFACE OF THE ACFT OTHER THAN THE MAIN GEAR). ALTHOUGH THE CTLS SEEMED TO BE FAIRLY INEFFECTIVE, I EVENTUALLY WAS ABLE TO GET THE ACFT ALIGNED WITH THE RWY. ALTHOUGH WE WERE ALIGNED WITH THE RWY, WE WERE ON THE FAR R EDGE OF IT. I COULD SEE US HDG STRAIGHT FOR THE RWY EDGE IDENT LIGHTS (AND MANY OBSTACLES OFF OF THE RWY). I KNEW WE WERE RUNNING OUT OF RWY AND DETERMINED THAT IT WOULD BE SAFER TO BE IN THE AIR THAN ON THE GND. I NOTED THAT MY AIRSPD WAS 45-50 KTS. AT THAT AIRSPD, I COULD HANDLE THE AIRPLANE BETTER IN THE AIR THAN ON THE GND. SO I APPLIED 10 DEGS OF FLAPS, ROTATED INTO GND EFFECT, ACCELERATED TO 60 KTS, AND PROCEEDED TO GO AROUND. ONCE THE ACFT WAS AIRBORNE AND STABILIZED, I RETURNED FOR LNDG. MY ESTIMATION OF THE TIME ELAPSED BTWN THE INITIAL YAW, AND THE TIME WE GOT AIRBORNE WAS 5-10 SECONDS. SYNOPSIS: TO THE BEST OF MY KNOWLEDGE, WE ENCOUNTERED A HORIZ WINDSHEAR. TO THE BEST OF MY UNDERSTANDING, WE WENT FROM HAVING A STRAIGHT HEADWIND TO A L QUARTERING TAILWIND. I BELIEVE 2 THINGS HAPPENED. FIRST, THE GUST FROM THE L LIFTED THE L WING UP. SECONDLY, THE SUDDEN SHIFT FROM A HEADWIND TO A TAILWIND REDUCED THE EFFECTIVE AIRFLOW OVER THE WING AND CTL SURFACES AT OR BELOW STALING SPDS. THUS THE ACFT MAY HAVE STALLED AND POSSIBLY ENTERED AN INITIAL SPIN. BEING SO CLOSE TO THE RWY, IT WAS IMPOSSIBLE TO RECOVER FROM THE HIGH RATE OF SINK. I BELIEVE THAT I FLEW THE AIRPLANE THE BEST IT COULD BE FLOWN FOR THE CONDITIONS AT HAND. HAD I NOT REACTED QUICKLY AND EFFECTIVELY, THE ACFT WOULD MOST LIKELY HAVE CARTWHEELED DOWN THE RWY RESULTING IN THE LOSS OF THE AIRPLANE AND POSSIBLY OUR LIVES.

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.