Pilot at 17500 ft reports encountering turbulence near lvm and inadvertently climbing to FL184.

Attributes
ACN	792965
Time
Date	200806
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : slc.airport
State Reference	UT
Altitude	msl single value : 17500
Environment
Flight Conditions	VMC
Weather Elements	Turbulence Windshear
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zlc.artcc
Operator	general aviation : personal
Make Model Name	Small Aircraft Low Wing 1 Eng Retractable Gear
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Experience	flight time last 90 days : 6 flight time total : 1255 flight time type : 32
ASRS Report	792965
Events
Anomaly	airspace violation : entry altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter other other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control
Supplementary
Problem Areas	Airspace Structure Weather
Primary Problem	Weather

Narrative:

Conditions were VFR with mostly clear skies with few scattered clouds and unlimited ceiling. I did not file a VFR flight plan but was on flight following from ZLC. Since I was flying over very high mountainous terrain; I chose to have as much altitude as possible and set a cruising altitude of 17500 ft. A high as possible altitude was chosen in case of emergency as I always do when crossing terrain. Upon approaching the front slopes of the beartooth mountain range; moderate to severe turbulence was encountered with a momentary altitude increase due to a strong updraft that pushed us into class a airspace. The aircraft reached approximately 18400 ft before I could stop the ascent with an abrupt and aggressive dive and return below positive control area. Flight then continued without further incident to destination.

Original NASA ASRS Text

Title: PILOT AT 17500 FT REPORTS ENCOUNTERING TURBULENCE NEAR LVM AND INADVERTENTLY CLIMBING TO FL184.

Narrative: CONDITIONS WERE VFR WITH MOSTLY CLR SKIES WITH FEW SCATTERED CLOUDS AND UNLIMITED CEILING. I DID NOT FILE A VFR FLT PLAN BUT WAS ON FLT FOLLOWING FROM ZLC. SINCE I WAS FLYING OVER VERY HIGH MOUNTAINOUS TERRAIN; I CHOSE TO HAVE AS MUCH ALT AS POSSIBLE AND SET A CRUISING ALT OF 17500 FT. A HIGH AS POSSIBLE ALT WAS CHOSEN IN CASE OF EMER AS I ALWAYS DO WHEN XING TERRAIN. UPON APCHING THE FRONT SLOPES OF THE BEARTOOTH MOUNTAIN RANGE; MODERATE TO SEVERE TURB WAS ENCOUNTERED WITH A MOMENTARY ALT INCREASE DUE TO A STRONG UPDRAFT THAT PUSHED US INTO CLASS A AIRSPACE. THE ACFT REACHED APPROX 18400 FT BEFORE I COULD STOP THE ASCENT WITH AN ABRUPT AND AGGRESSIVE DIVE AND RETURN BELOW PCA. FLT THEN CONTINUED WITHOUT FURTHER INCIDENT TO DEST.

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