A cl-300 captain reported encountering severe wake turbulence behind an MD11 in descent at FL240.

Attributes
ACN	887052
Time
Date	201005
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Challenger 300
Operating Under FAR Part	Part 91
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Inflight Event / Encounter Wake Vortex Encounter

Narrative:

While descending thru FL250 for FL240 we encountered severe wake turbulence from the aircraft in front of us. We first felt a little rumbling turbulence; quickly followed by the aircraft banking.

Original NASA ASRS Text

Title: A CL-300 Captain reported encountering severe wake turbulence behind an MD11 in descent at FL240.

Narrative: While descending thru FL250 for FL240 we encountered severe wake turbulence from the aircraft in front of us. We first felt a little rumbling turbulence; quickly followed by the aircraft banking.

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.