The flight crew of an light transport jet penetrated a thunderstorm while trying to clear the top. Loss of aircraft control resulted and the PF reversed course to exit the system. The aircraft deviated 2000 ft from the assigned altitude during the upset and the pilot's evasive maneuvers.

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Attributes
ACN	332381
Time
Date	199603
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : tlh
State Reference	FL
Altitude	msl bound lower : 43000 msl bound upper : 45000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air taxi
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 135
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : instrument pilot : commercial
Experience	flight time last 90 days : 50 flight time total : 4500 flight time type : 2500
ASRS Report	332381
Person 2
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment flight crew : returned to intended course or assigned course flight crew : regained aircraft control
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Upon reaching cruise at FL410 and completely aware of the thunderstorm activity ahead, it became evident that at FL410 we were not going to clear the tops of the storms. I requested and received FL430 to clear the thunderstorms and as we approached the storm we realized that we were not able to stay above the storm. Upon entering the tops we encountered severe turbulence and the aircraft became almost uncontrollable. The aircraft quickly exceeded mmo of .83 mach in which I reduced thrust and pitched up. Almost immediately the aircraft decelerated to near stall at 160 KIAS. Applying stall recovery techniques, I prevented us from stalling and immediately executed a 180 degree turn. During this encounter the altitude deviated from FL430 to FL450. No conflict existed. Upon exiting the WX system we maintained FL430 and flew approximately 200 mi out of our way. I believe my performance was good for the situation, however, my judgement in question. In the future I will be sure to go around rather than on top.

Original NASA ASRS Text

Title: THE FLC OF AN LTT JET PENETRATED A TSTM WHILE TRYING TO CLR THE TOP. LOSS OF ACFT CTL RESULTED AND THE PF REVERSED COURSE TO EXIT THE SYS. THE ACFT DEVIATED 2000 FT FROM THE ASSIGNED ALT DURING THE UPSET AND THE PLT'S EVASIVE MANEUVERS.

Narrative: UPON REACHING CRUISE AT FL410 AND COMPLETELY AWARE OF THE TSTM ACTIVITY AHEAD, IT BECAME EVIDENT THAT AT FL410 WE WERE NOT GOING TO CLR THE TOPS OF THE STORMS. I REQUESTED AND RECEIVED FL430 TO CLR THE TSTMS AND AS WE APCHED THE STORM WE REALIZED THAT WE WERE NOT ABLE TO STAY ABOVE THE STORM. UPON ENTERING THE TOPS WE ENCOUNTERED SEVERE TURB AND THE ACFT BECAME ALMOST UNCONTROLLABLE. THE ACFT QUICKLY EXCEEDED MMO OF .83 MACH IN WHICH I REDUCED THRUST AND PITCHED UP. ALMOST IMMEDIATELY THE ACFT DECELERATED TO NEAR STALL AT 160 KIAS. APPLYING STALL RECOVERY TECHNIQUES, I PREVENTED US FROM STALLING AND IMMEDIATELY EXECUTED A 180 DEG TURN. DURING THIS ENCOUNTER THE ALT DEVIATED FROM FL430 TO FL450. NO CONFLICT EXISTED. UPON EXITING THE WX SYS WE MAINTAINED FL430 AND FLEW APPROX 200 MI OUT OF OUR WAY. I BELIEVE MY PERFORMANCE WAS GOOD FOR THE SIT, HOWEVER, MY JUDGEMENT IN QUESTION. IN THE FUTURE I WILL BE SURE TO GAR RATHER THAN ON TOP.

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.