Narrative:

After 5-10 mins level at FL290 we took a handoff to ZJX. Just at that time we encounter several severe updrafts with a 3000 FPM climb on the vsi. I called for ignition override, kicked off the autoplt and kept the wings level. I was relatively heavy and my main concern was not to stall or exceed the 1-G negative load limitation by pushing the nose over to hold altitude. It was hard to keep focused on the instruments. Attitude and airspeed were my primary concerns, altitude was secondary. After a min or so of 'riding the waves' I got back down to FL290. I reported the deviation as soon as possible and the moderate to severe turbulence. I requested a higher altitude which was denied or a higher altitude with a turn which was also denied. After making the PIREP, an aircraft out ahead of me reported the same conditions after the fact. Also, north of craig, ZJX gave me information on numerous sigmets -- after the fact. None of this was available to me. If I had received a ride report of severe turbulence at FL290 which was experienced by an aircraft ahead of me I would have requested a route or lower altitude change to avoid it. Fortunately, I had the flight attendants and passenger in their seats and no injuries were reported. This deviation was not a result of missing a level off.

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Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION WHEN MLG EXPERIENCES AN INFLT ENCOUNTER WITH MODERATE TO SEVERE TURB.

Narrative: AFTER 5-10 MINS LEVEL AT FL290 WE TOOK A HDOF TO ZJX. JUST AT THAT TIME WE ENCOUNTER SEVERAL SEVERE UPDRAFTS WITH A 3000 FPM CLB ON THE VSI. I CALLED FOR IGNITION OVERRIDE, KICKED OFF THE AUTOPLT AND KEPT THE WINGS LEVEL. I WAS RELATIVELY HVY AND MY MAIN CONCERN WAS NOT TO STALL OR EXCEED THE 1-G NEGATIVE LOAD LIMITATION BY PUSHING THE NOSE OVER TO HOLD ALT. IT WAS HARD TO KEEP FOCUSED ON THE INSTS. ATTITUDE AND AIRSPD WERE MY PRIMARY CONCERNS, ALT WAS SECONDARY. AFTER A MIN OR SO OF 'RIDING THE WAVES' I GOT BACK DOWN TO FL290. I RPTED THE DEV ASAP AND THE MODERATE TO SEVERE TURB. I REQUESTED A HIGHER ALT WHICH WAS DENIED OR A HIGHER ALT WITH A TURN WHICH WAS ALSO DENIED. AFTER MAKING THE PIREP, AN ACFT OUT AHEAD OF ME RPTED THE SAME CONDITIONS AFTER THE FACT. ALSO, N OF CRAIG, ZJX GAVE ME INFO ON NUMEROUS SIGMETS -- AFTER THE FACT. NONE OF THIS WAS AVAILABLE TO ME. IF I HAD RECEIVED A RIDE RPT OF SEVERE TURB AT FL290 WHICH WAS EXPERIENCED BY AN ACFT AHEAD OF ME I WOULD HAVE REQUESTED A RTE OR LOWER ALT CHANGE TO AVOID IT. FORTUNATELY, I HAD THE FLT ATTENDANTS AND PAX IN THEIR SEATS AND NO INJURIES WERE RPTED. THIS DEV WAS NOT A RESULT OF MISSING A LEVEL OFF.

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.