Hot air balloon pilot had to land through fast forming fog.

Attributes
ACN	258838
Time
Date	199312
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mwo
State Reference	OH
Altitude	agl bound lower : 200 agl bound upper : 1000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other descent : approach landing other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp pilot : flight engineer pilot : cfi
Experience	flight time last 90 days : 180 flight time total : 3000 flight time type : 30
ASRS Report	258838
Events
Anomaly	inflight encounter : vfr in imc inflight encounter : weather non adherence : far other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Weather

Narrative:

Launched in good VMC conditions. While performing high altitude maneuvers, ground fog started to form. By the time I had descended to lower altitude, fog had formed over broad area and appeared to be 200-400 ft thick. Initially, I maintained a low altitude above fog deck looking for a landing area to become clear. After about 30 mins of holding, I maneuvered with reference to objects projecting above the fog and began slow descent. I established ground contact at approximately 100-200 ft AGL and from there was able to maneuver for a safe landing. Primary cause of incident was lack of awareness as to how quickly thick fog can form and not being more aggressive to land at first sign of fog formation. Callback conversation with reporter revealed the following: the reporter admits that this was the scariest situation that he has been in in 10 yrs of flying more than 1 type of aircraft. He had a proper WX briefing that indicated 'patchy' fog, not fog that stretched as far as he could see in the direction that he was drifting. The fog was only about 100 ft thick. It lasted only about an hour, but longer than his fuel supply would have allowed him to stay aloft.

Original NASA ASRS Text

Title: HOT AIR BALLOON PLT HAD TO LAND THROUGH FAST FORMING FOG.

Narrative: LAUNCHED IN GOOD VMC CONDITIONS. WHILE PERFORMING HIGH ALT MANEUVERS, GND FOG STARTED TO FORM. BY THE TIME I HAD DSNDED TO LOWER ALT, FOG HAD FORMED OVER BROAD AREA AND APPEARED TO BE 200-400 FT THICK. INITIALLY, I MAINTAINED A LOW ALT ABOVE FOG DECK LOOKING FOR A LNDG AREA TO BECOME CLR. AFTER ABOUT 30 MINS OF HOLDING, I MANEUVERED WITH REF TO OBJECTS PROJECTING ABOVE THE FOG AND BEGAN SLOW DSCNT. I ESTABLISHED GND CONTACT AT APPROX 100-200 FT AGL AND FROM THERE WAS ABLE TO MANEUVER FOR A SAFE LNDG. PRIMARY CAUSE OF INCIDENT WAS LACK OF AWARENESS AS TO HOW QUICKLY THICK FOG CAN FORM AND NOT BEING MORE AGGRESSIVE TO LAND AT FIRST SIGN OF FOG FORMATION. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THE RPTR ADMITS THAT THIS WAS THE SCARIEST SIT THAT HE HAS BEEN IN IN 10 YRS OF FLYING MORE THAN 1 TYPE OF ACFT. HE HAD A PROPER WX BRIEFING THAT INDICATED 'PATCHY' FOG, NOT FOG THAT STRETCHED AS FAR AS HE COULD SEE IN THE DIRECTION THAT HE WAS DRIFTING. THE FOG WAS ONLY ABOUT 100 FT THICK. IT LASTED ONLY ABOUT AN HR, BUT LONGER THAN HIS FUEL SUPPLY WOULD HAVE ALLOWED HIM TO STAY ALOFT.

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.