Narrative:

Following a normal departure we were cleared to FL290. During the climb out, we encountered light to occasional moderate turbulence, as anticipated from preflight paperwork and ATC. At FL290, 100 DME northwest of jvl VOR, we experienced an altitude increase and decrease of about 100 ft, similar to a mountain wave. At altitude, the sky was VFR with just a wisp of clouds about where the mountain wave occurred. (Note: there shouldn't have been a mountain wave, as we were not near any mountains. Within seconds of this altitude excursion, we encountered severe turbulence with loss of aircraft control. We descended, under some control, to FL210, where smooth air was encountered. During the descent, one galley cart hit the ceiling of the aircraft, flipped over, and landed on a flight attendant, spraying beverage and broken glass. All passenger were seated with seatbelts fastened. The flight attendant complained of back pain. No passenger injury. I don't know how to fix this problem as there must have been some upper air disturbance to cause this problem. My only observation or 'hint' that something might be upcoming was the apparent 'mountain wave' and the wispy cloud in the otherwise clear sky.

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Original NASA ASRS Text

Title: ACR MLG FLC LOST ACFT CTL DUE TO CLR AIR TURB. ONE CABIN ATTENDANT INJURED.

Narrative: FOLLOWING A NORMAL DEP WE WERE CLRED TO FL290. DURING THE CLBOUT, WE ENCOUNTERED LIGHT TO OCCASIONAL MODERATE TURB, AS ANTICIPATED FROM PREFLT PAPERWORK AND ATC. AT FL290, 100 DME NW OF JVL VOR, WE EXPERIENCED AN ALT INCREASE AND DECREASE OF ABOUT 100 FT, SIMILAR TO A MOUNTAIN WAVE. AT ALT, THE SKY WAS VFR WITH JUST A WISP OF CLOUDS ABOUT WHERE THE MOUNTAIN WAVE OCCURRED. (NOTE: THERE SHOULDN'T HAVE BEEN A MOUNTAIN WAVE, AS WE WERE NOT NEAR ANY MOUNTAINS. WITHIN SECONDS OF THIS ALT EXCURSION, WE ENCOUNTERED SEVERE TURB WITH LOSS OF ACFT CTL. WE DSNDED, UNDER SOME CTL, TO FL210, WHERE SMOOTH AIR WAS ENCOUNTERED. DURING THE DSCNT, ONE GALLEY CART HIT THE CEILING OF THE ACFT, FLIPPED OVER, AND LANDED ON A FLT ATTENDANT, SPRAYING BEVERAGE AND BROKEN GLASS. ALL PAX WERE SEATED WITH SEATBELTS FASTENED. THE FLT ATTENDANT COMPLAINED OF BACK PAIN. NO PAX INJURY. I DON'T KNOW HOW TO FIX THIS PROB AS THERE MUST HAVE BEEN SOME UPPER AIR DISTURBANCE TO CAUSE THIS PROB. MY ONLY OBSERVATION OR 'HINT' THAT SOMETHING MIGHT BE UPCOMING WAS THE APPARENT 'MOUNTAIN WAVE' AND THE WISPY CLOUD IN THE OTHERWISE CLR SKY.

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.