Narrative:

During flight planning, we noted in the remarks section that clear air turbulence was possible from gurar to E142 and calma to E163. Also possible cumulo nimbus to FL320 E142 to E148 and to FL300 W142 to W139 on track 1. These areas are marked on the plotting chart by the operations office in hkg. As a part of my flight attendant briefing I advised the chief purser of these areas and we discussed their impact on service. I was advised by the purser that it shouldn't be a problem since the area should be between services. In my pre-departure introduction to the passenger, I specifically alerted them to the possibility of unexpected turbulence and advised them to keep their seat belts fastened when seated. I also repeated that advice when I turned the seat belt sign off after takeoff. With the exception of a couple of brief periods of light chop, the flight had been smooth from level off to calma. Initial cruise altitude was FL290 but we had climbed to FL330 prior to calma. We were 3-4 mins behind flight X 2000 ft above us on the same route. Since we would be stuck below optimum altitudes for most of the flight if we stayed on track 1, I asked chidd if track 2 would be better. We never got any advice on the track 2 option, so just prior to calma we advised chidd that it was no longer an option and that we would stay on track 1. It was a dark night. The cockpit was dark so that could see out. Stars above and the horizon to the sides were visible. As we approached calma, we did not see any clouds. The radar was not on. Shortly after making our position report to tokyo radio at calma, we were advised that an air carrier B747 had reported moderate to severe turbulence at N41 E154. Since we were just past N40 approaching E152, I called the purser to check on the status of service and to alert her to the likelihood of turbulence in about 30-35 mi. I asked her to advise the rest of the flight attendant crew. Before I could turn on the seatbelt sign or she could advise the rest of her crew, we encountered a severe jolt. The first officer, the PF, reported a 20 KT gain and a 200 ft climb followed by a 40 KT loss AND400 ft descent in a matter of 2 or 3 seconds. I turned on the seat belt sign and the radar. I could now see that we were in the tops of some clouds. The radar in maximum and tilted 2-3 degrees down in 40 mi scale showed some green, but it looked more like ground return and it disappeared when normal was selected. I could see stars to the left, so I went to heading sel and turned left. We experienced a couple of mins of moderate turbulence and then another 15 or so mins of light to moderate chop as we were in and out of the tops. The radar gave no indication of cumulo nimbus activity ahead. We could not tell what was behind. Shortly after our event we heard the air carrier flight ahead of us tell an air carrier flight behind us that they had apparently hit the same turbulence at FL350. After several conversations with the chief purser and other flight attendants, it was determined that there were 6 injured passenger. The most serious injuries appeared to be to a 62 yr old woman, one of a group. She had been in an aft lavatory and was diagnosed by a doctor who was accompanying them to have sustained back and head injuries. An 83 yr old woman who was not wearing her seat belt hit her head on the seat in front and sustained a black eye. She was also treated by the doctor. I had the chief purser ask the doctor if either had sustained any life-threatening injuries or ones that required immediate hospital care. He said no, so we elected to continue to sfo. 4 other passenger sustained minor cuts and bumps. All of the injuries occurred toward the back of east zone. Initially none of the flight attendants indicated that they had been injured. Later, however, several complained of bumps, bruises, and stiffness. None asked for medical assistance. We advised chidd of the turbulence and the need for paramedics to meet the flight in sfo and that we would need an ambulance to transport the lady with the back injury to a hospital. The remainder of the flight was uneventful. We did not declare an emergency, but we were given expedited handling by ZOA, bay approach, and sfo tower. From the remarks and the WX briefing message we were aware of the possibility of turbulence in the area around calma, but we had no way of predicting that it would be so severe or occur without any warning. Because the area of possible turbulence and cumulo nimbus activity covered such a large area, and the flight had been smooth up to this point, I had considered it impractical to turn the seat belt sign on without some actual indication that the turbulence existed. The sign loses its effectiveness and the passenger generally disregard it if it is left on and the ride is smooth. Our flts from asia are usually planned in the vicinity of the highest winds, and it is not uncommon to encounter some turbulence en route, but I have never had turbulence of that magnitude occur without more moderate chop occurring first to give some warning. While I believe that this turbulence was associated with the jet stream, there is still the possibility that there was convective activity in the area. Because the WX radar was not on prior to the event, I have no way of knowing what we might have seen. The fact that 2 other airplanes seem to have encountered the same turbulence without seeing it makes me think that the radar would not have helped. I almost always leave the WX radar on moonless nights. I did not have it on this night and that will never happen again.

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Original NASA ASRS Text

Title: PERSONAL INJURY EXPERIENCED BY PAX WHEN ACR WDB HAS A CLR AIR TURB ENCOUNTER IN A NIGHT OVERWATER OP IN FOREIGN AIRSPACE.

Narrative: DURING FLT PLANNING, WE NOTED IN THE REMARKS SECTION THAT CLR AIR TURB WAS POSSIBLE FROM GURAR TO E142 AND CALMA TO E163. ALSO POSSIBLE CUMULO NIMBUS TO FL320 E142 TO E148 AND TO FL300 W142 TO W139 ON TRACK 1. THESE AREAS ARE MARKED ON THE PLOTTING CHART BY THE OPS OFFICE IN HKG. AS A PART OF MY FLT ATTENDANT BRIEFING I ADVISED THE CHIEF PURSER OF THESE AREAS AND WE DISCUSSED THEIR IMPACT ON SVC. I WAS ADVISED BY THE PURSER THAT IT SHOULDN'T BE A PROB SINCE THE AREA SHOULD BE BTWN SVCS. IN MY PRE-DEP INTRODUCTION TO THE PAX, I SPECIFICALLY ALERTED THEM TO THE POSSIBILITY OF UNEXPECTED TURB AND ADVISED THEM TO KEEP THEIR SEAT BELTS FASTENED WHEN SEATED. I ALSO REPEATED THAT ADVICE WHEN I TURNED THE SEAT BELT SIGN OFF AFTER TKOF. WITH THE EXCEPTION OF A COUPLE OF BRIEF PERIODS OF LIGHT CHOP, THE FLT HAD BEEN SMOOTH FROM LEVEL OFF TO CALMA. INITIAL CRUISE ALT WAS FL290 BUT WE HAD CLBED TO FL330 PRIOR TO CALMA. WE WERE 3-4 MINS BEHIND FLT X 2000 FT ABOVE US ON THE SAME RTE. SINCE WE WOULD BE STUCK BELOW OPTIMUM ALTS FOR MOST OF THE FLT IF WE STAYED ON TRACK 1, I ASKED CHIDD IF TRACK 2 WOULD BE BETTER. WE NEVER GOT ANY ADVICE ON THE TRACK 2 OPTION, SO JUST PRIOR TO CALMA WE ADVISED CHIDD THAT IT WAS NO LONGER AN OPTION AND THAT WE WOULD STAY ON TRACK 1. IT WAS A DARK NIGHT. THE COCKPIT WAS DARK SO THAT COULD SEE OUT. STARS ABOVE AND THE HORIZON TO THE SIDES WERE VISIBLE. AS WE APCHED CALMA, WE DID NOT SEE ANY CLOUDS. THE RADAR WAS NOT ON. SHORTLY AFTER MAKING OUR POS RPT TO TOKYO RADIO AT CALMA, WE WERE ADVISED THAT AN ACR B747 HAD RPTED MODERATE TO SEVERE TURB AT N41 E154. SINCE WE WERE JUST PAST N40 APCHING E152, I CALLED THE PURSER TO CHK ON THE STATUS OF SVC AND TO ALERT HER TO THE LIKELIHOOD OF TURB IN ABOUT 30-35 MI. I ASKED HER TO ADVISE THE REST OF THE FLT ATTENDANT CREW. BEFORE I COULD TURN ON THE SEATBELT SIGN OR SHE COULD ADVISE THE REST OF HER CREW, WE ENCOUNTERED A SEVERE JOLT. THE FO, THE PF, RPTED A 20 KT GAIN AND A 200 FT CLB FOLLOWED BY A 40 KT LOSS AND400 FT DSCNT IN A MATTER OF 2 OR 3 SECONDS. I TURNED ON THE SEAT BELT SIGN AND THE RADAR. I COULD NOW SEE THAT WE WERE IN THE TOPS OF SOME CLOUDS. THE RADAR IN MAX AND TILTED 2-3 DEGS DOWN IN 40 MI SCALE SHOWED SOME GREEN, BUT IT LOOKED MORE LIKE GND RETURN AND IT DISAPPEARED WHEN NORMAL WAS SELECTED. I COULD SEE STARS TO THE L, SO I WENT TO HDG SEL AND TURNED L. WE EXPERIENCED A COUPLE OF MINS OF MODERATE TURB AND THEN ANOTHER 15 OR SO MINS OF LIGHT TO MODERATE CHOP AS WE WERE IN AND OUT OF THE TOPS. THE RADAR GAVE NO INDICATION OF CUMULO NIMBUS ACTIVITY AHEAD. WE COULD NOT TELL WHAT WAS BEHIND. SHORTLY AFTER OUR EVENT WE HEARD THE ACR FLT AHEAD OF US TELL AN ACR FLT BEHIND US THAT THEY HAD APPARENTLY HIT THE SAME TURB AT FL350. AFTER SEVERAL CONVERSATIONS WITH THE CHIEF PURSER AND OTHER FLT ATTENDANTS, IT WAS DETERMINED THAT THERE WERE 6 INJURED PAX. THE MOST SERIOUS INJURIES APPEARED TO BE TO A 62 YR OLD WOMAN, ONE OF A GROUP. SHE HAD BEEN IN AN AFT LAVATORY AND WAS DIAGNOSED BY A DOCTOR WHO WAS ACCOMPANYING THEM TO HAVE SUSTAINED BACK AND HEAD INJURIES. AN 83 YR OLD WOMAN WHO WAS NOT WEARING HER SEAT BELT HIT HER HEAD ON THE SEAT IN FRONT AND SUSTAINED A BLACK EYE. SHE WAS ALSO TREATED BY THE DOCTOR. I HAD THE CHIEF PURSER ASK THE DOCTOR IF EITHER HAD SUSTAINED ANY LIFE-THREATENING INJURIES OR ONES THAT REQUIRED IMMEDIATE HOSPITAL CARE. HE SAID NO, SO WE ELECTED TO CONTINUE TO SFO. 4 OTHER PAX SUSTAINED MINOR CUTS AND BUMPS. ALL OF THE INJURIES OCCURRED TOWARD THE BACK OF E ZONE. INITIALLY NONE OF THE FLT ATTENDANTS INDICATED THAT THEY HAD BEEN INJURED. LATER, HOWEVER, SEVERAL COMPLAINED OF BUMPS, BRUISES, AND STIFFNESS. NONE ASKED FOR MEDICAL ASSISTANCE. WE ADVISED CHIDD OF THE TURB AND THE NEED FOR PARAMEDICS TO MEET THE FLT IN SFO AND THAT WE WOULD NEED AN AMBULANCE TO TRANSPORT THE LADY WITH THE BACK INJURY TO A HOSPITAL. THE REMAINDER OF THE FLT WAS UNEVENTFUL. WE DID NOT DECLARE AN EMER, BUT WE WERE GIVEN EXPEDITED HANDLING BY ZOA, BAY APCH, AND SFO TWR. FROM THE REMARKS AND THE WX BRIEFING MESSAGE WE WERE AWARE OF THE POSSIBILITY OF TURB IN THE AREA AROUND CALMA, BUT WE HAD NO WAY OF PREDICTING THAT IT WOULD BE SO SEVERE OR OCCUR WITHOUT ANY WARNING. BECAUSE THE AREA OF POSSIBLE TURB AND CUMULO NIMBUS ACTIVITY COVERED SUCH A LARGE AREA, AND THE FLT HAD BEEN SMOOTH UP TO THIS POINT, I HAD CONSIDERED IT IMPRACTICAL TO TURN THE SEAT BELT SIGN ON WITHOUT SOME ACTUAL INDICATION THAT THE TURB EXISTED. THE SIGN LOSES ITS EFFECTIVENESS AND THE PAX GENERALLY DISREGARD IT IF IT IS LEFT ON AND THE RIDE IS SMOOTH. OUR FLTS FROM ASIA ARE USUALLY PLANNED IN THE VICINITY OF THE HIGHEST WINDS, AND IT IS NOT UNCOMMON TO ENCOUNTER SOME TURB ENRTE, BUT I HAVE NEVER HAD TURB OF THAT MAGNITUDE OCCUR WITHOUT MORE MODERATE CHOP OCCURRING FIRST TO GIVE SOME WARNING. WHILE I BELIEVE THAT THIS TURB WAS ASSOCIATED WITH THE JET STREAM, THERE IS STILL THE POSSIBILITY THAT THERE WAS CONVECTIVE ACTIVITY IN THE AREA. BECAUSE THE WX RADAR WAS NOT ON PRIOR TO THE EVENT, I HAVE NO WAY OF KNOWING WHAT WE MIGHT HAVE SEEN. THE FACT THAT 2 OTHER AIRPLANES SEEM TO HAVE ENCOUNTERED THE SAME TURB WITHOUT SEEING IT MAKES ME THINK THAT THE RADAR WOULD NOT HAVE HELPED. I ALMOST ALWAYS LEAVE THE WX RADAR ON MOONLESS NIGHTS. I DID NOT HAVE IT ON THIS NIGHT AND THAT WILL NEVER HAPPEN AGAIN.

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.