Narrative:

While in a local practice area west of bolton field, I overhead bolton tower clearing a balloon for launch or liftoff (I forget exact wording). Balloon pilot made comment that he'd be 'operating northwest of airport.' tower responded 'operate at own risk.' shortly thereafter, tower broadcast closing down announcement (XA30 local), advisory frequency 128.1 (same as tower operating frequency). The active runway had been runway 22, with several aircraft landing there prior to tower closure. I made initial call inbound (1 mi north of small town) for full stop. Closer in, I observed 2 balloons just to northwest of approach end of runway 22 at estimated 800 ft AGL. I entered upwind 22 mi southwest of their position, and called upwind and then downwind (left pattern). I momentarily considered using runway 4, but rejected due to concern of potential head-on with aircraft (ramp is very close to approach end runway 22) and visibility poor. At no time after their initial contact with tower earlier did I hear any communication from balloon. Upon turning base to runway 22, I observed one of the balloons seemed lower than before relative to other, and had drifted closer to extended runway centerline. I cut an angling base to final turn earlier than I originally intended, which was extent of 'evasive maneuver.' higher than normal approach, no sweat in bi-plane. Upon taxi back from landing, I noticed balloon touching down 3/4 mi northeast of threshold runway 22 in open field on extended centerline. There was never any collision danger as balloon never remained stationary in view, and original base turn was even, or slightly inside balloon path. I don't know if my presence in pattern caused balloon to adjust his flight path, or not, or if he were concerned about separation. How do you 'cut out' a balloon when both our landing sites are slightly different? Some factors: 1) recent liftoff (it may have been 'other' balloon) led me to expect that balloon would be slowly departing area. 2) if balloon had communicated intention of landing near approach end, I, runway 22, would have landed on runway 4 (wind was light), instead. 3) control tower closing may have induced balloon pilots to shut off radio, not a good thing with CTAF available. 4) it really is difficult to gauge just what balloon is doing.

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Original NASA ASRS Text

Title: NMAC BTWN A CHRISTEN EAGLE TURNING FROM BASE LEG ON FINAL AND A HOT AIR BALLOON DSNDING WITHIN 1 MI OFF THE ACTIVE RWY THRESHOLD.

Narrative: WHILE IN A LCL PRACTICE AREA W OF BOLTON FIELD, I OVERHEAD BOLTON TWR CLRING A BALLOON FOR LAUNCH OR LIFTOFF (I FORGET EXACT WORDING). BALLOON PLT MADE COMMENT THAT HE'D BE 'OPERATING NW OF ARPT.' TWR RESPONDED 'OPERATE AT OWN RISK.' SHORTLY THEREAFTER, TWR BROADCAST CLOSING DOWN ANNOUNCEMENT (XA30 LCL), ADVISORY FREQ 128.1 (SAME AS TWR OPERATING FREQ). THE ACTIVE RWY HAD BEEN RWY 22, WITH SEVERAL ACFT LNDG THERE PRIOR TO TWR CLOSURE. I MADE INITIAL CALL INBOUND (1 MI N OF SMALL TOWN) FOR FULL STOP. CLOSER IN, I OBSERVED 2 BALLOONS JUST TO NW OF APCH END OF RWY 22 AT ESTIMATED 800 FT AGL. I ENTERED UPWIND 22 MI SW OF THEIR POS, AND CALLED UPWIND AND THEN DOWNWIND (L PATTERN). I MOMENTARILY CONSIDERED USING RWY 4, BUT REJECTED DUE TO CONCERN OF POTENTIAL HEAD-ON WITH ACFT (RAMP IS VERY CLOSE TO APCH END RWY 22) AND VISIBILITY POOR. AT NO TIME AFTER THEIR INITIAL CONTACT WITH TWR EARLIER DID I HEAR ANY COM FROM BALLOON. UPON TURNING BASE TO RWY 22, I OBSERVED ONE OF THE BALLOONS SEEMED LOWER THAN BEFORE RELATIVE TO OTHER, AND HAD DRIFTED CLOSER TO EXTENDED RWY CTRLINE. I CUT AN ANGLING BASE TO FINAL TURN EARLIER THAN I ORIGINALLY INTENDED, WHICH WAS EXTENT OF 'EVASIVE MANEUVER.' HIGHER THAN NORMAL APCH, NO SWEAT IN BI-PLANE. UPON TAXI BACK FROM LNDG, I NOTICED BALLOON TOUCHING DOWN 3/4 MI NE OF THRESHOLD RWY 22 IN OPEN FIELD ON EXTENDED CTRLINE. THERE WAS NEVER ANY COLLISION DANGER AS BALLOON NEVER REMAINED STATIONARY IN VIEW, AND ORIGINAL BASE TURN WAS EVEN, OR SLIGHTLY INSIDE BALLOON PATH. I DON'T KNOW IF MY PRESENCE IN PATTERN CAUSED BALLOON TO ADJUST HIS FLT PATH, OR NOT, OR IF HE WERE CONCERNED ABOUT SEPARATION. HOW DO YOU 'CUT OUT' A BALLOON WHEN BOTH OUR LNDG SITES ARE SLIGHTLY DIFFERENT? SOME FACTORS: 1) RECENT LIFTOFF (IT MAY HAVE BEEN 'OTHER' BALLOON) LED ME TO EXPECT THAT BALLOON WOULD BE SLOWLY DEPARTING AREA. 2) IF BALLOON HAD COMMUNICATED INTENTION OF LNDG NEAR APCH END, I, RWY 22, WOULD HAVE LANDED ON RWY 4 (WIND WAS LIGHT), INSTEAD. 3) CTL TWR CLOSING MAY HAVE INDUCED BALLOON PLTS TO SHUT OFF RADIO, NOT A GOOD THING WITH CTAF AVAILABLE. 4) IT REALLY IS DIFFICULT TO GAUGE JUST WHAT BALLOON IS DOING.

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.