Narrative:

We were on climb out after takeoff from fra, copilot flying the aircraft. Encountering light to moderate turbulence at FL280. The captain had just made a PA about staying in seats with seat belt fastened. Requested and received clearance to climb to FL310. Initially, turbulence eased, but just as we were leveling at FL310, we encountered severe turbulence. I was on the jumpseat, the aircraft shook so violently my sunglasses and headset came off. The copilot started a descent, the captain initially could not make a radio call because the airplane was shaking so violently he couldn't use a microphone switch. While descending, the TCASII showed a traffic conflict and issued an RA, the copilot had visually acquired the traffic and evaded. In the descent we got to about 22500 ft, then climbed to level at FL230 in moderate turbulence. I used the interphone to check with a flight attendant about passenger. She said everyone appeared to be ok, but she needed to check on one in the back who might have hit his head. Later, she confirmed that everyone was ok. We requested clearance back to frankfurt, which we got. Return and landing were uneventful, and had airplane checked for structural damage (none found). All 3 flight deck crew members agreed that this was, by far, the most severe turbulence they had ever encountered, and for the longest duration. I realize there is a tendency to think events last longer than actually happens, and still estimate that we were in continuous severe turbulence for 3-4 mins. Afterwards, in talking about it, the captain said the first time he could read the altimeter after the encounter started, we were descending through FL270 and things really didn't settle back to moderate until we reached FL230. We all thought there was a good possibility of structural damage because the encounter was so violent. In conclusion: 1) manufacturer builds one hell of an airplane. 2) TCASII was useful in acquiring and avoiding another aircraft during our forced descent. 3) the fact that the captain had just made a PA about seat belts may have contributed to our not experiencing any injuries to passenger.

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Original NASA ASRS Text

Title: WDB ACFT ENCOUNTERS SEVERE TURB AT LEVEL OFF. RETURN LAND FOR STRUCTURAL INSPECTION.

Narrative: WE WERE ON CLBOUT AFTER TKOF FROM FRA, COPLT FLYING THE ACFT. ENCOUNTERING LIGHT TO MODERATE TURB AT FL280. THE CAPT HAD JUST MADE A PA ABOUT STAYING IN SEATS WITH SEAT BELT FASTENED. REQUESTED AND RECEIVED CLRNC TO CLB TO FL310. INITIALLY, TURB EASED, BUT JUST AS WE WERE LEVELING AT FL310, WE ENCOUNTERED SEVERE TURB. I WAS ON THE JUMPSEAT, THE ACFT SHOOK SO VIOLENTLY MY SUNGLASSES AND HEADSET CAME OFF. THE COPLT STARTED A DSCNT, THE CAPT INITIALLY COULD NOT MAKE A RADIO CALL BECAUSE THE AIRPLANE WAS SHAKING SO VIOLENTLY HE COULDN'T USE A MIKE SWITCH. WHILE DSNDING, THE TCASII SHOWED A TFC CONFLICT AND ISSUED AN RA, THE COPLT HAD VISUALLY ACQUIRED THE TFC AND EVADED. IN THE DSCNT WE GOT TO ABOUT 22500 FT, THEN CLBED TO LEVEL AT FL230 IN MODERATE TURB. I USED THE INTERPHONE TO CHK WITH A FLT ATTENDANT ABOUT PAX. SHE SAID EVERYONE APPEARED TO BE OK, BUT SHE NEEDED TO CHK ON ONE IN THE BACK WHO MIGHT HAVE HIT HIS HEAD. LATER, SHE CONFIRMED THAT EVERYONE WAS OK. WE REQUESTED CLRNC BACK TO FRANKFURT, WHICH WE GOT. RETURN AND LNDG WERE UNEVENTFUL, AND HAD AIRPLANE CHKED FOR STRUCTURAL DAMAGE (NONE FOUND). ALL 3 FLT DECK CREW MEMBERS AGREED THAT THIS WAS, BY FAR, THE MOST SEVERE TURB THEY HAD EVER ENCOUNTERED, AND FOR THE LONGEST DURATION. I REALIZE THERE IS A TENDENCY TO THINK EVENTS LAST LONGER THAN ACTUALLY HAPPENS, AND STILL ESTIMATE THAT WE WERE IN CONTINUOUS SEVERE TURB FOR 3-4 MINS. AFTERWARDS, IN TALKING ABOUT IT, THE CAPT SAID THE FIRST TIME HE COULD READ THE ALTIMETER AFTER THE ENCOUNTER STARTED, WE WERE DSNDING THROUGH FL270 AND THINGS REALLY DIDN'T SETTLE BACK TO MODERATE UNTIL WE REACHED FL230. WE ALL THOUGHT THERE WAS A GOOD POSSIBILITY OF STRUCTURAL DAMAGE BECAUSE THE ENCOUNTER WAS SO VIOLENT. IN CONCLUSION: 1) MANUFACTURER BUILDS ONE HELL OF AN AIRPLANE. 2) TCASII WAS USEFUL IN ACQUIRING AND AVOIDING ANOTHER ACFT DURING OUR FORCED DSCNT. 3) THE FACT THAT THE CAPT HAD JUST MADE A PA ABOUT SEAT BELTS MAY HAVE CONTRIBUTED TO OUR NOT EXPERIENCING ANY INJURIES TO PAX.

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.