Narrative:

This incident occurred at night in IFR conditions at FL390. The aircraft encountered turbulence that lasted approximately 10-15 seconds. Prior to encountering the turbulence; there was no indication of any WX displayed on the WX radar. The radar was tilted down 2 degrees and was on a 160 NM scale. The cockpit lights were turned down and visual checks outside were accomplished periodically. However; the conditions were not conducive to observing WX visually. It was very dark with little to no moon to illuminate any convective WX. It was my impression that we had overflown a buildup. Initial reaction from the aircraft was a pitch up with a slight altitude gain of 100-200 ft. The aircraft settled down after the encounter with no further incident. The captain called the cabin crew and determined there were several injuries to flight attendants and some passenger. The captain continued coordination and with the flight attendants while contacting dispatch and station operations to have medical personnel meet the aircraft. The aircraft was recovered normally into ZZZZ. After landing; the injured flight attendants and passenger were taken to a clinic at the airport. Since no x-ray facilities were available; the flight attendants were taken to a local hospital for further evaluation.

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Original NASA ASRS Text

Title: B777 FLIGHT CREW ENCOUNTERS UNREPORTED TURBULENCE AT FL390 CAUSING INJURIES TO PASSENGERS AND FLIGHT ATTENDANTS. FLIGHT CONTINUES TO DESTINATION.

Narrative: THIS INCIDENT OCCURRED AT NIGHT IN IFR CONDITIONS AT FL390. THE ACFT ENCOUNTERED TURB THAT LASTED APPROX 10-15 SECONDS. PRIOR TO ENCOUNTERING THE TURB; THERE WAS NO INDICATION OF ANY WX DISPLAYED ON THE WX RADAR. THE RADAR WAS TILTED DOWN 2 DEGS AND WAS ON A 160 NM SCALE. THE COCKPIT LIGHTS WERE TURNED DOWN AND VISUAL CHKS OUTSIDE WERE ACCOMPLISHED PERIODICALLY. HOWEVER; THE CONDITIONS WERE NOT CONDUCIVE TO OBSERVING WX VISUALLY. IT WAS VERY DARK WITH LITTLE TO NO MOON TO ILLUMINATE ANY CONVECTIVE WX. IT WAS MY IMPRESSION THAT WE HAD OVERFLOWN A BUILDUP. INITIAL REACTION FROM THE ACFT WAS A PITCH UP WITH A SLIGHT ALT GAIN OF 100-200 FT. THE ACFT SETTLED DOWN AFTER THE ENCOUNTER WITH NO FURTHER INCIDENT. THE CAPT CALLED THE CABIN CREW AND DETERMINED THERE WERE SEVERAL INJURIES TO FLT ATTENDANTS AND SOME PAX. THE CAPT CONTINUED COORD AND WITH THE FLT ATTENDANTS WHILE CONTACTING DISPATCH AND STATION OPS TO HAVE MEDICAL PERSONNEL MEET THE ACFT. THE ACFT WAS RECOVERED NORMALLY INTO ZZZZ. AFTER LNDG; THE INJURED FLT ATTENDANTS AND PAX WERE TAKEN TO A CLINIC AT THE ARPT. SINCE NO X-RAY FACILITIES WERE AVAILABLE; THE FLT ATTENDANTS WERE TAKEN TO A LOCAL HOSPITAL FOR FURTHER EVALUATION.

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.