Narrative:

Flight mission was a private pilot student training flight. This flight was to include VOR and NDB intercept and tracking, simulated instrument, and landing practice. I obtained a duat WX brief about 1 hour before the flight. VFR conditions with occasional snow showers. There was an airmet for moderate turbulence over most of the midwest. Winds at takeoff were from 180 degrees at 14 KTS, however, other nearby airports were reporting gusts in the low 20's. Spent about 1 1/2 hours in the practice area where we experienced light turbulence. As we approached the airport, ATIS reported the winds from 180 degrees at 20 KTS gusting to 27 KTS. Based on the conditions, I decided to forgo landing practice and complete a full stop landing. Arriving in the traffic pattern, I briefed my student (who was the PF) about the conditions, ie, minimum flap settings, crosswind technique, and windshear awareness. Arriving on final approach to runway 14, we experienced moderate to severe turbulence and windshear. Unable to land, my student elected to go around. We informed the tower we were going around after which the controller offered us a left downwind entry to runway 23. We accepted and I, as instructor, took over control of the airplane. Again, we encountered turbulence and windshear. I was able to maintain control of the airplane (with great effort) up until about 50 ft above the runway when turbulence and shear forced a go around in order to maintain control of the aircraft. We advised the tower and were instructed to enter a right pattern for a second attempt of runway 23. We were cleared to land behind a falcon jet. The jet landed without reporting any shear, so we attempted another approach. On short final we again experienced turbulence and shear. At this point, I advised the tower we would like to change back to runway 14. We were cleared to go around and enter a left downwind to runway 14. Again we experienced turbulence and shear. I kept our approach speed high and was about 20 KTS fast over the threshold. I was able to land the airplane, and taxi back to parking. After debriefing my student, he advised me we had a 20 KT instantaneous drop in airspeed just before touchdown.

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Original NASA ASRS Text

Title: C172 STUDENT AND INSTRUCTOR ENCOUNTER TURB AND WINDSHEAR IN LNDG PATTERN. SUCCESSFUL LNDG ACCOMPLISHED AFTER 3 GAR'S.

Narrative: FLT MISSION WAS A PVT PLT STUDENT TRAINING FLT. THIS FLT WAS TO INCLUDE VOR AND NDB INTERCEPT AND TRACKING, SIMULATED INST, AND LNDG PRACTICE. I OBTAINED A DUAT WX BRIEF ABOUT 1 HR BEFORE THE FLT. VFR CONDITIONS WITH OCCASIONAL SNOW SHOWERS. THERE WAS AN AIRMET FOR MODERATE TURB OVER MOST OF THE MIDWEST. WINDS AT TKOF WERE FROM 180 DEGS AT 14 KTS, HOWEVER, OTHER NEARBY ARPTS WERE RPTING GUSTS IN THE LOW 20'S. SPENT ABOUT 1 1/2 HRS IN THE PRACTICE AREA WHERE WE EXPERIENCED LIGHT TURB. AS WE APCHED THE ARPT, ATIS RPTED THE WINDS FROM 180 DEGS AT 20 KTS GUSTING TO 27 KTS. BASED ON THE CONDITIONS, I DECIDED TO FORGO LNDG PRACTICE AND COMPLETE A FULL STOP LNDG. ARRIVING IN THE TFC PATTERN, I BRIEFED MY STUDENT (WHO WAS THE PF) ABOUT THE CONDITIONS, IE, MINIMUM FLAP SETTINGS, XWIND TECHNIQUE, AND WINDSHEAR AWARENESS. ARRIVING ON FINAL APCH TO RWY 14, WE EXPERIENCED MODERATE TO SEVERE TURB AND WINDSHEAR. UNABLE TO LAND, MY STUDENT ELECTED TO GO AROUND. WE INFORMED THE TWR WE WERE GOING AROUND AFTER WHICH THE CTLR OFFERED US A L DOWNWIND ENTRY TO RWY 23. WE ACCEPTED AND I, AS INSTRUCTOR, TOOK OVER CTL OF THE AIRPLANE. AGAIN, WE ENCOUNTERED TURB AND WINDSHEAR. I WAS ABLE TO MAINTAIN CTL OF THE AIRPLANE (WITH GREAT EFFORT) UP UNTIL ABOUT 50 FT ABOVE THE RWY WHEN TURB AND SHEAR FORCED A GAR IN ORDER TO MAINTAIN CTL OF THE ACFT. WE ADVISED THE TWR AND WERE INSTRUCTED TO ENTER A R PATTERN FOR A SECOND ATTEMPT OF RWY 23. WE WERE CLRED TO LAND BEHIND A FALCON JET. THE JET LANDED WITHOUT RPTING ANY SHEAR, SO WE ATTEMPTED ANOTHER APCH. ON SHORT FINAL WE AGAIN EXPERIENCED TURB AND SHEAR. AT THIS POINT, I ADVISED THE TWR WE WOULD LIKE TO CHANGE BACK TO RWY 14. WE WERE CLRED TO GO AROUND AND ENTER A L DOWNWIND TO RWY 14. AGAIN WE EXPERIENCED TURB AND SHEAR. I KEPT OUR APCH SPD HIGH AND WAS ABOUT 20 KTS FAST OVER THE THRESHOLD. I WAS ABLE TO LAND THE AIRPLANE, AND TAXI BACK TO PARKING. AFTER DEBRIEFING MY STUDENT, HE ADVISED ME WE HAD A 20 KT INSTANTANEOUS DROP IN AIRSPD JUST BEFORE TOUCHDOWN.

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.