In-flight microburst encounter. Reporter pilot, towing a banner and flying at 1300 ft AGL hit strong...

Attributes
ACN	346001
Time
Date	199609
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : apa airport : 48v
State Reference	CO
Altitude	agl bound lower : 300 agl bound upper : 1300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PA-18/19 Super Cub
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial
Experience	flight time last 90 days : 100 flight time total : 3000 flight time type : 600
ASRS Report	346001
Events
Anomaly	conflict : ground less severe inflight encounter : weather other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment none taken : unable
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

Between XA35 and XA53 pm, between apa and downtown denver I encountered a strong downdraft. I was pulling a banner at 6500 ft MSL when it started. It took me down very strongly (500 FPM plus) and I was looking for an empty area in which to drop the banner. I found an unused baseball complex and began circling it preparatory to dropping the banner and/or landing if necessary. I had been flying for over 2 hours so I was lighter because of the fuel used (approximately 96 pounds). I would estimate that I was at about 300 ft AGL at times as I circled at full power. I finally began to regain altitude and was at about 500 ft AGL when I moved north about 1/4 mi to a larger open area. After about 10 mins of this, I had regained 6500 ft and continued my flight. I was talking to another banner tow plane on 122.75 at the time of this operation and he told me that a big downburst had hit him at mile high stadium (northwest of me) and he had to leave to get out of it. He said that it was coming my way. I was already in it when he told me this. There were several downbursts (microbursts) in the denver area that afternoon. I had to fly west to bjc in order to return from downtown denver to 48V (tri- county/erie) to avoid a particularly large one. I don't know what I could have done differently to prevent this.

Original NASA ASRS Text

Title: INFLT MICROBURST ENCOUNTER. RPTR PLT, TOWING A BANNER AND FLYING AT 1300 FT AGL HIT STRONG DOWNDRAFT, LOST 1000 FT. PLT FLEW OUT OF IT AND REGAINED ALT, BUT DIVERTED AROUND OTHER MICROBURSTS TO RETURN TO HIS HOME ARPT. WX FACTORS STRONG DOWNDRAFT, MICROBURST.

Narrative: BTWN XA35 AND XA53 PM, BTWN APA AND DOWNTOWN DENVER I ENCOUNTERED A STRONG DOWNDRAFT. I WAS PULLING A BANNER AT 6500 FT MSL WHEN IT STARTED. IT TOOK ME DOWN VERY STRONGLY (500 FPM PLUS) AND I WAS LOOKING FOR AN EMPTY AREA IN WHICH TO DROP THE BANNER. I FOUND AN UNUSED BASEBALL COMPLEX AND BEGAN CIRCLING IT PREPARATORY TO DROPPING THE BANNER AND/OR LNDG IF NECESSARY. I HAD BEEN FLYING FOR OVER 2 HRS SO I WAS LIGHTER BECAUSE OF THE FUEL USED (APPROX 96 LBS). I WOULD ESTIMATE THAT I WAS AT ABOUT 300 FT AGL AT TIMES AS I CIRCLED AT FULL PWR. I FINALLY BEGAN TO REGAIN ALT AND WAS AT ABOUT 500 FT AGL WHEN I MOVED N ABOUT 1/4 MI TO A LARGER OPEN AREA. AFTER ABOUT 10 MINS OF THIS, I HAD REGAINED 6500 FT AND CONTINUED MY FLT. I WAS TALKING TO ANOTHER BANNER TOW PLANE ON 122.75 AT THE TIME OF THIS OP AND HE TOLD ME THAT A BIG DOWNBURST HAD HIT HIM AT MILE HIGH STADIUM (NW OF ME) AND HE HAD TO LEAVE TO GET OUT OF IT. HE SAID THAT IT WAS COMING MY WAY. I WAS ALREADY IN IT WHEN HE TOLD ME THIS. THERE WERE SEVERAL DOWNBURSTS (MICROBURSTS) IN THE DENVER AREA THAT AFTERNOON. I HAD TO FLY W TO BJC IN ORDER TO RETURN FROM DOWNTOWN DENVER TO 48V (TRI- COUNTY/ERIE) TO AVOID A PARTICULARLY LARGE ONE. I DON'T KNOW WHAT I COULD HAVE DONE DIFFERENTLY TO PREVENT THIS.

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.

In-flight microburst encounter. Reporter pilot, towing a banner and flying at 1300 ft AGL hit strong downdraft, lost 1000 ft. Pilot flew out of it and regained altitude, but diverted around other microbursts to return to his home airport. WX factors strong downdraft, microburst.