M20 pilot has a class a airspace violation while encountering strong updrafts.

Attributes
ACN	703419
Time
Date	200607
Local Time Of Day	0601 To 1200
Place
Locale Reference	navaid : mtu.vortac
State Reference	UT
Altitude	msl bound lower : 17500 msl bound upper : 19000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	M-20 K (231)
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	VFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : commercial
Experience	flight time last 90 days : 20 flight time total : 5000 flight time type : 1500
ASRS Report	703419
Events
Anomaly	airspace violation : entry altitude deviation : overshoot altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : far non adherence : clearance
Independent Detector	other controllerb other flight crewa
Resolutory Action	flight crew : regained aircraft control flight crew : returned to assigned airspace flight crew : returned to assigned altitude
Supplementary
Problem Areas	Environmental Factor Aircraft Weather Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

I called great falls FSS about XA30 and asked for an outlook briefing. At about XD30 called FSS again and told the briefer that I had an outlook and I received a brief update. I should have asked for the full briefing. Took off for vernal approximately XE00 and landed at vernal XG15. Closed with cedar city. Refueled and departed vernal XQ45. Sky had increased in the number of clouds but still appeared scattered. Cedar city only said 'mountain tops obscured;' when flight plan opened. We had cleared all clouds at 13500 ft coming into vernal and assumed they; the cloud tops; would be cleared to the south by 15500. Wrong! We had smooth updrafts 1000-1500 FPM. We were at 17500 ft and thought the altitude hold had been set. Apparently not; as I soon observed FL180 and FL190. We found a hole as soon as possible and descended. I understood that the WX at home was to have the thunderstorms develop later. This was not as predicted. My first knowledge of a convective SIGMET was 5 mi from home. We landed VFR after the heavy rain and hail passed.

Original NASA ASRS Text

Title: M20 PLT HAS A CLASS A AIRSPACE VIOLATION WHILE ENCOUNTERING STRONG UPDRAFTS.

Narrative: I CALLED GREAT FALLS FSS ABOUT XA30 AND ASKED FOR AN OUTLOOK BRIEFING. AT ABOUT XD30 CALLED FSS AGAIN AND TOLD THE BRIEFER THAT I HAD AN OUTLOOK AND I RECEIVED A BRIEF UPDATE. I SHOULD HAVE ASKED FOR THE FULL BRIEFING. TOOK OFF FOR VERNAL APPROX XE00 AND LANDED AT VERNAL XG15. CLOSED WITH CEDAR CITY. REFUELED AND DEPARTED VERNAL XQ45. SKY HAD INCREASED IN THE NUMBER OF CLOUDS BUT STILL APPEARED SCATTERED. CEDAR CITY ONLY SAID 'MOUNTAIN TOPS OBSCURED;' WHEN FLT PLAN OPENED. WE HAD CLRED ALL CLOUDS AT 13500 FT COMING INTO VERNAL AND ASSUMED THEY; THE CLOUD TOPS; WOULD BE CLRED TO THE S BY 15500. WRONG! WE HAD SMOOTH UPDRAFTS 1000-1500 FPM. WE WERE AT 17500 FT AND THOUGHT THE ALT HOLD HAD BEEN SET. APPARENTLY NOT; AS I SOON OBSERVED FL180 AND FL190. WE FOUND A HOLE ASAP AND DSNDED. I UNDERSTOOD THAT THE WX AT HOME WAS TO HAVE THE TSTMS DEVELOP LATER. THIS WAS NOT AS PREDICTED. MY FIRST KNOWLEDGE OF A CONVECTIVE SIGMET WAS 5 MI FROM HOME. WE LANDED VFR AFTER THE HVY RAIN AND HAIL PASSED.

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