Narrative:

We were at FL230 in the cruise phase of flight. We had the radar on and were proceeding on the polar arrival into detroit. We were in clear air with a cell 40 NM off our left and cells on the radar. The captain had swept the radar from the ground to 10 degrees above and saw no cells in front of us. We had just turned off the seatbelt sign and we were eating our meals. The aircraft shuddered and our meal trays on our tables lifted to eye level. They then slammed down launching food off both of our trays and all over the screens; table; floors; sides; and us. This happened again twice. I reached for the seatbelt sign to get it back on and missed it twice. I saw the captain try twice too; but we both missed the switch. He then placed his hand onto his tray to prevent it from flying again. I grabbed the PA and told the flight attendants to take their seat immediately. The captain observed that the autoplt was overcorrecting and switched off the autoplt and flew it through the turbulence. The severe turbulence lasted approximately 10 seconds. Once it stopped; we were in smooth air. We got the seatbelt sign turned on just as the turbulence stopped. We were proceeding towards light rain. I called the back to make sure that everyone was all right. The flight attendants said that they were uninjured; but the service cart had come off the ground a few times and liquid was everywhere. I asked them to make sure that no one was injured and to report back to us. We reported to center that we had encountered severe turbulence and gave a position report. We sent a message to the company giving the same report. The flight attendants called and told us that no one was injured; but 1 passenger did have hot coffee spilled on her. We continued to detroit without further incident. We dodged cells the rest of the way to detroit and had the flight attendants stay seated for most of the duration of the flight. On the ground; it was apparent that no one was injured; just shaken up a bit. The cockpit and cabin were a mess. We sent the appropriate messages to maintenance and dispatch and regrouped for a quick debrief.

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Original NASA ASRS Text

Title: AN A320 CREW REPORTED SEVERE CLEAR AIR TURBULENCE ENROUTE TO DTW. NO INJURIES RESULTED. TSTMS WERE IN THE VICINITY.

Narrative: WE WERE AT FL230 IN THE CRUISE PHASE OF FLT. WE HAD THE RADAR ON AND WERE PROCEEDING ON THE POLAR ARR INTO DETROIT. WE WERE IN CLR AIR WITH A CELL 40 NM OFF OUR L AND CELLS ON THE RADAR. THE CAPT HAD SWEPT THE RADAR FROM THE GND TO 10 DEGS ABOVE AND SAW NO CELLS IN FRONT OF US. WE HAD JUST TURNED OFF THE SEATBELT SIGN AND WE WERE EATING OUR MEALS. THE ACFT SHUDDERED AND OUR MEAL TRAYS ON OUR TABLES LIFTED TO EYE LEVEL. THEY THEN SLAMMED DOWN LAUNCHING FOOD OFF BOTH OF OUR TRAYS AND ALL OVER THE SCREENS; TABLE; FLOORS; SIDES; AND US. THIS HAPPENED AGAIN TWICE. I REACHED FOR THE SEATBELT SIGN TO GET IT BACK ON AND MISSED IT TWICE. I SAW THE CAPT TRY TWICE TOO; BUT WE BOTH MISSED THE SWITCH. HE THEN PLACED HIS HAND ONTO HIS TRAY TO PREVENT IT FROM FLYING AGAIN. I GRABBED THE PA AND TOLD THE FLT ATTENDANTS TO TAKE THEIR SEAT IMMEDIATELY. THE CAPT OBSERVED THAT THE AUTOPLT WAS OVERCORRECTING AND SWITCHED OFF THE AUTOPLT AND FLEW IT THROUGH THE TURB. THE SEVERE TURB LASTED APPROX 10 SECONDS. ONCE IT STOPPED; WE WERE IN SMOOTH AIR. WE GOT THE SEATBELT SIGN TURNED ON JUST AS THE TURB STOPPED. WE WERE PROCEEDING TOWARDS LIGHT RAIN. I CALLED THE BACK TO MAKE SURE THAT EVERYONE WAS ALL RIGHT. THE FLT ATTENDANTS SAID THAT THEY WERE UNINJURED; BUT THE SVC CART HAD COME OFF THE GND A FEW TIMES AND LIQUID WAS EVERYWHERE. I ASKED THEM TO MAKE SURE THAT NO ONE WAS INJURED AND TO RPT BACK TO US. WE RPTED TO CTR THAT WE HAD ENCOUNTERED SEVERE TURB AND GAVE A POS RPT. WE SENT A MESSAGE TO THE COMPANY GIVING THE SAME RPT. THE FLT ATTENDANTS CALLED AND TOLD US THAT NO ONE WAS INJURED; BUT 1 PAX DID HAVE HOT COFFEE SPILLED ON HER. WE CONTINUED TO DETROIT WITHOUT FURTHER INCIDENT. WE DODGED CELLS THE REST OF THE WAY TO DETROIT AND HAD THE FLT ATTENDANTS STAY SEATED FOR MOST OF THE DURATION OF THE FLT. ON THE GND; IT WAS APPARENT THAT NO ONE WAS INJURED; JUST SHAKEN UP A BIT. THE COCKPIT AND CABIN WERE A MESS. WE SENT THE APPROPRIATE MESSAGES TO MAINT AND DISPATCH AND REGROUPED FOR A QUICK DEBRIEF.

Data retrieved from NASA's ASRS site as of May 2009 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.