Narrative:

After flying low level, 200-300' AGL, and attempting to land 3 times previously after making an initial approach from 1200' AGL, (the winds shifted each time, making lndgs impractical due to the proximity of power lines) I was making another attempt to land on the east side of coors blvd in a large field, when the winds not only again shifted back to the west and south, but I also encountered an unusual downdraft. This resulted in a descent from the 75-100' I expected to be at, to about 40'. The shift also took the balloon on a path that was at first head on into the oncoming traffic on the road, and then back toward the power lines on the west side of coors blvd. Landing in the middle of coors not being an option, and knowing I could clear the power lines, I ascended to 1300' AGL, and landed a short time later 1 mi west. I had checked the winds below me several times during the approach to the east side of coors, and they were consistently going to the east where I planned to land. However, since they had shifted slightly on my previous approachs, I tried to leave plenty of room to abort that landing also if necessary. However, the unexpected quick descent of the balloon left me little room for error, and caused traffic on the highway to slow with the concern that I may land on the road. Since I am still not positive what caused the descent, it is difficult to suggest corrective action other than a more thorough study of micro-meteorology. I am already aware of the causes of 'false lift,' and this did not appear to me to be the cause of this descent. The same type of descent also occurred on my final landing over an open field where it was not as much of a concern, and I was prepared for it.

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Original NASA ASRS Text

Title: BALLOONIST ATTEMPTING TO LAND ON FIELD ADJACENT TO ROAD WITH TRAFFIC INADVERTENTLY DRIFTED INTO THE PATH OF AUTOS, BUT MANAGED TO ASCEND AND LATER EFFECT A SAFE LNDG.

Narrative: AFTER FLYING LOW LEVEL, 200-300' AGL, AND ATTEMPTING TO LAND 3 TIMES PREVIOUSLY AFTER MAKING AN INITIAL APCH FROM 1200' AGL, (THE WINDS SHIFTED EACH TIME, MAKING LNDGS IMPRACTICAL DUE TO THE PROX OF PWR LINES) I WAS MAKING ANOTHER ATTEMPT TO LAND ON THE E SIDE OF COORS BLVD IN A LARGE FIELD, WHEN THE WINDS NOT ONLY AGAIN SHIFTED BACK TO THE W AND S, BUT I ALSO ENCOUNTERED AN UNUSUAL DOWNDRAFT. THIS RESULTED IN A DSCNT FROM THE 75-100' I EXPECTED TO BE AT, TO ABOUT 40'. THE SHIFT ALSO TOOK THE BALLOON ON A PATH THAT WAS AT FIRST HEAD ON INTO THE ONCOMING TFC ON THE ROAD, AND THEN BACK TOWARD THE PWR LINES ON THE W SIDE OF COORS BLVD. LNDG IN THE MIDDLE OF COORS NOT BEING AN OPTION, AND KNOWING I COULD CLR THE PWR LINES, I ASCENDED TO 1300' AGL, AND LANDED A SHORT TIME LATER 1 MI W. I HAD CHKED THE WINDS BELOW ME SEVERAL TIMES DURING THE APCH TO THE E SIDE OF COORS, AND THEY WERE CONSISTENTLY GOING TO THE E WHERE I PLANNED TO LAND. HOWEVER, SINCE THEY HAD SHIFTED SLIGHTLY ON MY PREVIOUS APCHS, I TRIED TO LEAVE PLENTY OF ROOM TO ABORT THAT LNDG ALSO IF NECESSARY. HOWEVER, THE UNEXPECTED QUICK DSCNT OF THE BALLOON LEFT ME LITTLE ROOM FOR ERROR, AND CAUSED TFC ON THE HWY TO SLOW WITH THE CONCERN THAT I MAY LAND ON THE ROAD. SINCE I AM STILL NOT POSITIVE WHAT CAUSED THE DSCNT, IT IS DIFFICULT TO SUGGEST CORRECTIVE ACTION OTHER THAN A MORE THOROUGH STUDY OF MICRO-METEOROLOGY. I AM ALREADY AWARE OF THE CAUSES OF 'FALSE LIFT,' AND THIS DID NOT APPEAR TO ME TO BE THE CAUSE OF THIS DSCNT. THE SAME TYPE OF DSCNT ALSO OCCURRED ON MY FINAL LNDG OVER AN OPEN FIELD WHERE IT WAS NOT AS MUCH OF A CONCERN, AND I WAS PREPARED FOR IT.

Data retrieved from NASA's ASRS site as of August 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.