Narrative:

Was given a straight in approach to runway xxr at ZZZ; winds were light and from approximately 030 degree; as I can recall. Landing was full flaps wheel landing; which was normal. After touchdown; the aircraft veered suddenly to the left. At the same time the left wing was lifted indicating a gust from the left. Full left aileron; right rudder; and power was added to correct the situation. Left aileron was successful in lowering the left wing; however the aircraft continued the turn to the left; right brake was now applied with no result as the tire was heard to be slipping on the pavement. The loop was too developed. The aircraft then departed the runway xxr to left side; missing the runway edge lights; but as the tail came around the elevator hit a runway distance marker. No damage was done to the distance marker; with the exception that it was broken free from the frangible mounts. The elevator received minor damage from striking the distance marker. After the incident; I received a phone call from an individual who watched the landing from the south ramp at the airport. Before the aircraft touched down he noticed the windsock was 'limp' and after the aircraft touched down he noticed the windsock suddenly went 'straight out.' immediately following this he noticed the aircraft I was flying suddenly veer to the left. The incident was caused by a sudden; unexpected gust of wind from the left resulting in a ground loop. This is not the first time I have experienced this type of unexpected wind shift and or gust at this airport on this same runway. Previous events were able to be controled with uneventful lndgs. While I will be more diligent in the landing sequence; a sudden gust of wind or wind shift; when these conditions are not forecasted or reported; during a landing in a tailwheel aircraft; or any aircraft is something that cannot be anticipated. The installation of windsocks at the touchdown zones of the runways could help to prevent further incidents by indicating the wind direction and speed at the location where it is most important. Not at the middle of the airport; or midway down the runway. In previous operations at ZZZ I have noticed that the wind direction given by the control tower can be; at times; vastly different than the wind direction depicted by windsock. In one previous event the wind direction was given as 320 degrees; and the windsock was depicting a wind direction of approximately 270 degrees. This was noted while on approach to landing on runway xxr in the same aircraft (as in this incident) and seeing the 'open end' of the windsock; which would be a quartering left tailwind. A go around was performed with an uneventful landing on runway xyl.

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Original NASA ASRS Text

Title: A PILOT REPORTS GND LOOPING HIS ACFT AFTER AN UNEXPECTED WIND GUST HIT THE ACFT IN THE LANDING FLARE.

Narrative: WAS GIVEN A STRAIGHT IN APCH TO RWY XXR AT ZZZ; WINDS WERE LIGHT AND FROM APPROX 030 DEG; AS I CAN RECALL. LNDG WAS FULL FLAPS WHEEL LNDG; WHICH WAS NORMAL. AFTER TOUCHDOWN; THE ACFT VEERED SUDDENLY TO THE L. AT THE SAME TIME THE L WING WAS LIFTED INDICATING A GUST FROM THE L. FULL L AILERON; R RUDDER; AND PWR WAS ADDED TO CORRECT THE SITUATION. L AILERON WAS SUCCESSFUL IN LOWERING THE L WING; HOWEVER THE ACFT CONTINUED THE TURN TO THE L; R BRAKE WAS NOW APPLIED WITH NO RESULT AS THE TIRE WAS HEARD TO BE SLIPPING ON THE PAVEMENT. THE LOOP WAS TOO DEVELOPED. THE ACFT THEN DEPARTED THE RWY XXR TO L SIDE; MISSING THE RWY EDGE LIGHTS; BUT AS THE TAIL CAME AROUND THE ELEVATOR HIT A RWY DISTANCE MARKER. NO DAMAGE WAS DONE TO THE DISTANCE MARKER; WITH THE EXCEPTION THAT IT WAS BROKEN FREE FROM THE FRANGIBLE MOUNTS. THE ELEVATOR RECEIVED MINOR DAMAGE FROM STRIKING THE DISTANCE MARKER. AFTER THE INCIDENT; I RECEIVED A PHONE CALL FROM AN INDIVIDUAL WHO WATCHED THE LNDG FROM THE S RAMP AT THE ARPT. BEFORE THE ACFT TOUCHED DOWN HE NOTICED THE WINDSOCK WAS 'LIMP' AND AFTER THE ACFT TOUCHED DOWN HE NOTICED THE WINDSOCK SUDDENLY WENT 'STRAIGHT OUT.' IMMEDIATELY FOLLOWING THIS HE NOTICED THE ACFT I WAS FLYING SUDDENLY VEER TO THE L. THE INCIDENT WAS CAUSED BY A SUDDEN; UNEXPECTED GUST OF WIND FROM THE L RESULTING IN A GND LOOP. THIS IS NOT THE FIRST TIME I HAVE EXPERIENCED THIS TYPE OF UNEXPECTED WIND SHIFT AND OR GUST AT THIS ARPT ON THIS SAME RWY. PREVIOUS EVENTS WERE ABLE TO BE CTLED WITH UNEVENTFUL LNDGS. WHILE I WILL BE MORE DILIGENT IN THE LNDG SEQUENCE; A SUDDEN GUST OF WIND OR WIND SHIFT; WHEN THESE CONDITIONS ARE NOT FORECASTED OR RPTED; DURING A LNDG IN A TAILWHEEL ACFT; OR ANY ACFT IS SOMETHING THAT CANNOT BE ANTICIPATED. THE INSTALLATION OF WINDSOCKS AT THE TOUCHDOWN ZONES OF THE RWYS COULD HELP TO PREVENT FURTHER INCIDENTS BY INDICATING THE WIND DIRECTION AND SPD AT THE LOCATION WHERE IT IS MOST IMPORTANT. NOT AT THE MIDDLE OF THE ARPT; OR MIDWAY DOWN THE RWY. IN PREVIOUS OPS AT ZZZ I HAVE NOTICED THAT THE WIND DIRECTION GIVEN BY THE CTL TWR CAN BE; AT TIMES; VASTLY DIFFERENT THAN THE WIND DIRECTION DEPICTED BY WINDSOCK. IN ONE PREVIOUS EVENT THE WIND DIRECTION WAS GIVEN AS 320 DEGS; AND THE WINDSOCK WAS DEPICTING A WIND DIRECTION OF APPROX 270 DEGS. THIS WAS NOTED WHILE ON APCH TO LNDG ON RWY XXR IN THE SAME ACFT (AS IN THIS INCIDENT) AND SEEING THE 'OPEN END' OF THE WINDSOCK; WHICH WOULD BE A QUARTERING L TAILWIND. A GAR WAS PERFORMED WITH AN UNEVENTFUL LNDG ON RWY XYL.

Data retrieved from NASA's ASRS site as of May 2009 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.