Lear 60 loses 600 feet in turbulence encounter at FL410.

Attributes
ACN	824862
Time
Date	200902
Local Time Of Day	1801-2400
Place
Locale Reference	ZTL.ARTCC
State Reference	GA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Learjet 60
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Autopilot
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 60 Flight Crew Total 23100 Flight Crew Type 5500
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter Weather / Turbulence

Narrative:

At cruise at FL410 southbound and encountered sudden severe turbulence and autopilot overreacted and lost 600 ft of altitude. Fell to FL404 and ATC did call us to confirm altitude deviation. Advised ATC of encounter with sudden turbulence and correcting altitude. No other comments were made by ATC; or was there any conflict. The learjet 60 model is very sensitive at high altitude in turbulence. No other aircraft involved an RA or any!

Original NASA ASRS Text

Title: Lear 60 loses 600 feet in turbulence encounter at FL410.

Narrative: At cruise at FL410 southbound and encountered sudden severe turbulence and autopilot overreacted and lost 600 FT of altitude. Fell to FL404 and ATC did call us to confirm altitude deviation. Advised ATC of encounter with sudden turbulence and correcting altitude. No other comments were made by ATC; or was there any conflict. The Learjet 60 model is very sensitive at high altitude in turbulence. No other aircraft involved an RA or any!

Data retrieved from NASA's ASRS site as of April 2012 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.