Narrative:

Scheduled from lax-tpa, B757. Full passenger load with 6 flight attendants on board. Prior to departure reviewed WX for trip with particular review of route through tx, la, and the gulf for thunderstorm activity and turbulence. Moderate turbulence forecast to FL330. Our planned cruise was at FL370. Captain talked to flight control dispatch for updated information. Dispatch was also called while over NM to review WX and developments. No changes from forecast. Across tx, noted a couple of large cells south of our route via aircraft radar. No deviations were necessary, 30-35 NM clearance on route. Between lfk-hrv with seat belt sign on, we received a call from ZHU that an aircraft in our area had reported moderate-severe turbulence with an altitude gain of 1000 ft. As the first officer, I acknowledged the call and immediately made a PA that everyone was to rechk the security of their seat belts, the flight attendants were to terminate their service and take their seats immediately as we were entering a dangerous area. Within about 1 min the aircraft started a climb (even though the autoplt was engaged in altitude hold). At 37200 ft the captain disengaged the autoplt and leveled the aircraft at 37400 ft. Almost immediately we hit sharp severe turbulence for about 5 seconds. Then it was smooth again as it had been. We reported the encounter to ZHU. I checked with the 'a' flight attendant and she said there appeared to be some problems in the aft. We were switched to ZJX. I called flight control and coordinated a plan. As reports came to the cockpit of injuries, we started looking for the nearest suitable airport. Physicians on board reviewed the injuries and I relayed the information to the dispatcher. Msy, btr were ruled out due to WX and turbulence. 1 flight attendant was thrown against the ceiling and a service cart fell on her. The physician recommended not moving her and avoiding any known turbulence. With the input from the physician and WX along the gulf coast not favorable it was jointly decided to continue to tpa, now about 40 mins ahead. We declared a medical emergency with ZJX near nepta intersection. ZMA coordinated our arrival into tpa. We landed on runway 18L and rolled to the end to avoid a quick deceleration on the injured passenger. We taxied to the gate and were met by medical/rescue personnel. The final report showed 2 flight attendants and 6 passenger were treated at local hospitals. The flight attendants were released that evening with bruises and back sprain. I do not know how serious the passenger injuries were, but the flight attendant was considered the worst case at the aircraft. We wrote up the event in the aircraft logbook as an 'encounter with severe and unusual turbulence.' all aircraft system operated normally for the duration of the flight and maintenance found no problems during their postflt inspection. No panels were dislodged in the aircraft and all passenger who had their seat belts on were not injured. We elected to proceed to tpa due to WX considerations and medical capability. Turbulence is hard to predict and passenger do not feel compelled to obey the lit 'seat belt sign.' the injuries most likely resulted from the rapid and sudden on-set of the turbulence. It had been smooth the entire trip with this one exception. Again this is a pitfall. The flight was operating normally above a cirrus cloud layer in clear skies. The cloud deck was 1000-2000 ft below the aircraft. There appeared to be widespread cumulo nimbus activity well below our flight level, but no returns were on the WX radar.

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Original NASA ASRS Text

Title: B757-200 ACFT IN CRUISE ENCOUNTERED SEVERE TURB RESULTING IN INJURIES TO CABIN ATTENDANTS AND PAX. EMER DECLARED AND FLT CONTINUED TO DEST DUE TO WX CONDITIONS AT CLOSER ARPTS.

Narrative: SCHEDULED FROM LAX-TPA, B757. FULL PAX LOAD WITH 6 FLT ATTENDANTS ON BOARD. PRIOR TO DEP REVIEWED WX FOR TRIP WITH PARTICULAR REVIEW OF RTE THROUGH TX, LA, AND THE GULF FOR TSTM ACTIVITY AND TURB. MODERATE TURB FORECAST TO FL330. OUR PLANNED CRUISE WAS AT FL370. CAPT TALKED TO FLT CTL DISPATCH FOR UPDATED INFO. DISPATCH WAS ALSO CALLED WHILE OVER NM TO REVIEW WX AND DEVELOPMENTS. NO CHANGES FROM FORECAST. ACROSS TX, NOTED A COUPLE OF LARGE CELLS S OF OUR RTE VIA ACFT RADAR. NO DEVS WERE NECESSARY, 30-35 NM CLRNC ON RTE. BTWN LFK-HRV WITH SEAT BELT SIGN ON, WE RECEIVED A CALL FROM ZHU THAT AN ACFT IN OUR AREA HAD RPTED MODERATE-SEVERE TURB WITH AN ALT GAIN OF 1000 FT. AS THE FO, I ACKNOWLEDGED THE CALL AND IMMEDIATELY MADE A PA THAT EVERYONE WAS TO RECHK THE SECURITY OF THEIR SEAT BELTS, THE FLT ATTENDANTS WERE TO TERMINATE THEIR SVC AND TAKE THEIR SEATS IMMEDIATELY AS WE WERE ENTERING A DANGEROUS AREA. WITHIN ABOUT 1 MIN THE ACFT STARTED A CLB (EVEN THOUGH THE AUTOPLT WAS ENGAGED IN ALT HOLD). AT 37200 FT THE CAPT DISENGAGED THE AUTOPLT AND LEVELED THE ACFT AT 37400 FT. ALMOST IMMEDIATELY WE HIT SHARP SEVERE TURB FOR ABOUT 5 SECONDS. THEN IT WAS SMOOTH AGAIN AS IT HAD BEEN. WE RPTED THE ENCOUNTER TO ZHU. I CHKED WITH THE 'A' FLT ATTENDANT AND SHE SAID THERE APPEARED TO BE SOME PROBS IN THE AFT. WE WERE SWITCHED TO ZJX. I CALLED FLT CTL AND COORDINATED A PLAN. AS RPTS CAME TO THE COCKPIT OF INJURIES, WE STARTED LOOKING FOR THE NEAREST SUITABLE ARPT. PHYSICIANS ON BOARD REVIEWED THE INJURIES AND I RELAYED THE INFO TO THE DISPATCHER. MSY, BTR WERE RULED OUT DUE TO WX AND TURB. 1 FLT ATTENDANT WAS THROWN AGAINST THE CEILING AND A SVC CART FELL ON HER. THE PHYSICIAN RECOMMENDED NOT MOVING HER AND AVOIDING ANY KNOWN TURB. WITH THE INPUT FROM THE PHYSICIAN AND WX ALONG THE GULF COAST NOT FAVORABLE IT WAS JOINTLY DECIDED TO CONTINUE TO TPA, NOW ABOUT 40 MINS AHEAD. WE DECLARED A MEDICAL EMER WITH ZJX NEAR NEPTA INTXN. ZMA COORDINATED OUR ARR INTO TPA. WE LANDED ON RWY 18L AND ROLLED TO THE END TO AVOID A QUICK DECELERATION ON THE INJURED PAX. WE TAXIED TO THE GATE AND WERE MET BY MEDICAL/RESCUE PERSONNEL. THE FINAL RPT SHOWED 2 FLT ATTENDANTS AND 6 PAX WERE TREATED AT LCL HOSPITALS. THE FLT ATTENDANTS WERE RELEASED THAT EVENING WITH BRUISES AND BACK SPRAIN. I DO NOT KNOW HOW SERIOUS THE PAX INJURIES WERE, BUT THE FLT ATTENDANT WAS CONSIDERED THE WORST CASE AT THE ACFT. WE WROTE UP THE EVENT IN THE ACFT LOGBOOK AS AN 'ENCOUNTER WITH SEVERE AND UNUSUAL TURB.' ALL ACFT SYS OPERATED NORMALLY FOR THE DURATION OF THE FLT AND MAINT FOUND NO PROBS DURING THEIR POSTFLT INSPECTION. NO PANELS WERE DISLODGED IN THE ACFT AND ALL PAX WHO HAD THEIR SEAT BELTS ON WERE NOT INJURED. WE ELECTED TO PROCEED TO TPA DUE TO WX CONSIDERATIONS AND MEDICAL CAPABILITY. TURB IS HARD TO PREDICT AND PAX DO NOT FEEL COMPELLED TO OBEY THE LIT 'SEAT BELT SIGN.' THE INJURIES MOST LIKELY RESULTED FROM THE RAPID AND SUDDEN ON-SET OF THE TURB. IT HAD BEEN SMOOTH THE ENTIRE TRIP WITH THIS ONE EXCEPTION. AGAIN THIS IS A PITFALL. THE FLT WAS OPERATING NORMALLY ABOVE A CIRRUS CLOUD LAYER IN CLR SKIES. THE CLOUD DECK WAS 1000-2000 FT BELOW THE ACFT. THERE APPEARED TO BE WIDESPREAD CUMULO NIMBUS ACTIVITY WELL BELOW OUR FLT LEVEL, BUT NO RETURNS WERE ON THE WX RADAR.

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.