Severe clear air turbulence encounter at FL370.

Attributes
ACN	541218
Time
Date	200203
Day	Mon
Local Time Of Day	1201 To 1800
Place
State Reference	TX
Altitude	msl bound lower : 37000 msl bound upper : 39300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhu.artcc
Operator	common carrier : air carrier
Make Model Name	A319
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : atp pilot : flight engineer pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 210 flight time total : 18000 flight time type : 6000
ASRS Report	541218
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather inflight encounter other other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control flight crew : returned to assigned altitude
Consequence	other
Supplementary
Problem Areas	Weather
Primary Problem	Weather

Narrative:

At FL370 we hit some severe clear air turbulence that put the aircraft in a 30 KT overspd. Vsi was climbing at 7000+ FPM. Recovered aircraft at FL393. Advised ATC, returned to FL370. No passenger or crew hurt. Callback conversation with reporter revealed the following information: the WX was clear with some convective activity some distance to the west. There was a jetstream with reported speeds up to 160 KTS to the south. It is suspected that the encounter was with this jetstream. There were no previous reports. There was an automatic autoplt disconnect followed by uncontrolled climb with vertical speed indicator pegged at the up limit. Climb topped out above the service ceiling of the airplane with airspeed approaching stall. There were no traffic conflicts as a result of the altitude excursion.

Original NASA ASRS Text

Title: SEVERE CLR AIR TURB ENCOUNTER AT FL370.

Narrative: AT FL370 WE HIT SOME SEVERE CLR AIR TURB THAT PUT THE ACFT IN A 30 KT OVERSPD. VSI WAS CLBING AT 7000+ FPM. RECOVERED ACFT AT FL393. ADVISED ATC, RETURNED TO FL370. NO PAX OR CREW HURT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE WX WAS CLR WITH SOME CONVECTIVE ACTIVITY SOME DISTANCE TO THE W. THERE WAS A JETSTREAM WITH RPTED SPDS UP TO 160 KTS TO THE S. IT IS SUSPECTED THAT THE ENCOUNTER WAS WITH THIS JETSTREAM. THERE WERE NO PREVIOUS RPTS. THERE WAS AN AUTOMATIC AUTOPLT DISCONNECT FOLLOWED BY UNCTLED CLB WITH VERT SPD INDICATOR PEGGED AT THE UP LIMIT. CLB TOPPED OUT ABOVE THE SVC CEILING OF THE AIRPLANE WITH AIRSPD APCHING STALL. THERE WERE NO TFC CONFLICTS AS A RESULT OF THE ALT EXCURSION.

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.