Narrative:

Altitude loss of 400', 12000' assigned (11600') due to severe turbulence, over mountains associated with thunderstorm low level wind shear. Corrected as soon as possible -- aircraft was uncontrollable for approximately 1 min. Fluctuations as much as 40 KTS in airspeed, control movement were full aileron at one time. This was accompanied with mountain wave.

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Original NASA ASRS Text

Title: SEVERE TURBULENCE IN DEN AREA. CPR JET SUFFERS LOSS OF ACFT CTL AND EXPERIENCES AN ALT DEVIATION.

Narrative: ALT LOSS OF 400', 12000' ASSIGNED (11600') DUE TO SEVERE TURBULENCE, OVER MOUNTAINS ASSOCIATED WITH TSTM LOW LEVEL WIND SHEAR. CORRECTED ASAP -- ACFT WAS UNCONTROLLABLE FOR APPROX 1 MIN. FLUCTUATIONS AS MUCH AS 40 KTS IN AIRSPEED, CONTROL MOVEMENT WERE FULL AILERON AT ONE TIME. THIS WAS ACCOMPANIED WITH MOUNTAIN WAVE.

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.