Narrative:

We were descending in clear skies about 80 mi from the west coast of the san francisco bay area. It was nighttime. Radar was on and using various tilt settings was not painting anything of significance (a speckling of green returns out in the distance). We had no reports of bad rides. As we passed through about FL290, we encountered a sudden and rapid increase in airspeed that exceeded the maximum airspeed allowed. The autoplt simultaneously began to pull the nose up. I disengaged the autoplt and continued to bring the nose up. However, when I disengaged the autoplt there was an accompanying small to moderate jerk. Combined with the pitch up, the jerk, and what was now suddenly moderate turbulence, some of the passenger were jostled around. The event lasted about 5-10 seconds. I turned on the seatbelt sign and called to inquire if everyone was ok. After the ride smoothed somewhat, the flight attendants surveyed the cabin and determined 1 female passenger, a doctor, said she had hurt her foot. 1 flight attendant said she may have twisted her neck. No one wanted to have medical personnel meet the aircraft upon arrival. We made the appropriate logbook entries and gave a PIREP to ATC. After arrival, everyone was fine (we received numerous passenger compliments for a job well done), except the doctor now thought her foot 'could' be broken. In-flight supervisors were called and they took a statement from her. She refused medical care, and also did not want a wheelchair. She was urged to use the wheelchair several times, but steadfastly refused. She appeared to me to be walking without the need for assistance. Still, without an x-ray, it is difficult to determine the extent, if any, of her injury. While I feel bad that this occurred, I don't know what else I could have done. Both of us were well rested and were alert and paying attention. This definitely fits the definition of 'unexpected turbulence.' supplemental information from acn 641463: I noticed the airspeed had crept above target by about 5-10 KTS and was about to pull the throttles back when it seemed like we hit what I would call a smooth mountain wave that accelerated the aircraft approximately 30 KTS almost instantly. By the time I had my hand on the throttles, so did the captain, and we both made sure it was in full idle but the mach warning and overspd system had already taken over. The overspd condition was over in 5-10 seconds and the speed brakes were deployed to stabilize the condition as soon as possible. We were still getting moderate chop to moderate turbulence in clear air and the captain immediately turned on the seatbelt sign. I continued to hand fly the aircraft with the speed brakes out to get the aircraft below target airspeed and below the profile by about 900 ft. After about 1 min, I re-engaged the autoplt, took the aircraft out of VNAV and put it into flight level change mode and changed the speed to 280 KTS as the turbulence seemed to dissipate to light chop, occasional smooth.

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Original NASA ASRS Text

Title: FLT CREW OF B777-200 ENCOUNTER CLR AIR TURB 80 MI W OF OSI ON DSCNT INTO SFO.

Narrative: WE WERE DSNDING IN CLR SKIES ABOUT 80 MI FROM THE WEST COAST OF THE SAN FRANCISCO BAY AREA. IT WAS NIGHTTIME. RADAR WAS ON AND USING VARIOUS TILT SETTINGS WAS NOT PAINTING ANYTHING OF SIGNIFICANCE (A SPECKLING OF GREEN RETURNS OUT IN THE DISTANCE). WE HAD NO RPTS OF BAD RIDES. AS WE PASSED THROUGH ABOUT FL290, WE ENCOUNTERED A SUDDEN AND RAPID INCREASE IN AIRSPD THAT EXCEEDED THE MAX AIRSPD ALLOWED. THE AUTOPLT SIMULTANEOUSLY BEGAN TO PULL THE NOSE UP. I DISENGAGED THE AUTOPLT AND CONTINUED TO BRING THE NOSE UP. HOWEVER, WHEN I DISENGAGED THE AUTOPLT THERE WAS AN ACCOMPANYING SMALL TO MODERATE JERK. COMBINED WITH THE PITCH UP, THE JERK, AND WHAT WAS NOW SUDDENLY MODERATE TURB, SOME OF THE PAX WERE JOSTLED AROUND. THE EVENT LASTED ABOUT 5-10 SECONDS. I TURNED ON THE SEATBELT SIGN AND CALLED TO INQUIRE IF EVERYONE WAS OK. AFTER THE RIDE SMOOTHED SOMEWHAT, THE FLT ATTENDANTS SURVEYED THE CABIN AND DETERMINED 1 FEMALE PAX, A DOCTOR, SAID SHE HAD HURT HER FOOT. 1 FLT ATTENDANT SAID SHE MAY HAVE TWISTED HER NECK. NO ONE WANTED TO HAVE MEDICAL PERSONNEL MEET THE ACFT UPON ARR. WE MADE THE APPROPRIATE LOGBOOK ENTRIES AND GAVE A PIREP TO ATC. AFTER ARR, EVERYONE WAS FINE (WE RECEIVED NUMEROUS PAX COMPLIMENTS FOR A JOB WELL DONE), EXCEPT THE DOCTOR NOW THOUGHT HER FOOT 'COULD' BE BROKEN. INFLT SUPVRS WERE CALLED AND THEY TOOK A STATEMENT FROM HER. SHE REFUSED MEDICAL CARE, AND ALSO DID NOT WANT A WHEELCHAIR. SHE WAS URGED TO USE THE WHEELCHAIR SEVERAL TIMES, BUT STEADFASTLY REFUSED. SHE APPEARED TO ME TO BE WALKING WITHOUT THE NEED FOR ASSISTANCE. STILL, WITHOUT AN X-RAY, IT IS DIFFICULT TO DETERMINE THE EXTENT, IF ANY, OF HER INJURY. WHILE I FEEL BAD THAT THIS OCCURRED, I DON'T KNOW WHAT ELSE I COULD HAVE DONE. BOTH OF US WERE WELL RESTED AND WERE ALERT AND PAYING ATTN. THIS DEFINITELY FITS THE DEFINITION OF 'UNEXPECTED TURB.' SUPPLEMENTAL INFO FROM ACN 641463: I NOTICED THE AIRSPD HAD CREPT ABOVE TARGET BY ABOUT 5-10 KTS AND WAS ABOUT TO PULL THE THROTTLES BACK WHEN IT SEEMED LIKE WE HIT WHAT I WOULD CALL A SMOOTH MOUNTAIN WAVE THAT ACCELERATED THE ACFT APPROX 30 KTS ALMOST INSTANTLY. BY THE TIME I HAD MY HAND ON THE THROTTLES, SO DID THE CAPT, AND WE BOTH MADE SURE IT WAS IN FULL IDLE BUT THE MACH WARNING AND OVERSPD SYS HAD ALREADY TAKEN OVER. THE OVERSPD CONDITION WAS OVER IN 5-10 SECONDS AND THE SPD BRAKES WERE DEPLOYED TO STABILIZE THE CONDITION ASAP. WE WERE STILL GETTING MODERATE CHOP TO MODERATE TURB IN CLR AIR AND THE CAPT IMMEDIATELY TURNED ON THE SEATBELT SIGN. I CONTINUED TO HAND FLY THE ACFT WITH THE SPD BRAKES OUT TO GET THE ACFT BELOW TARGET AIRSPD AND BELOW THE PROFILE BY ABOUT 900 FT. AFTER ABOUT 1 MIN, I RE-ENGAGED THE AUTOPLT, TOOK THE ACFT OUT OF VNAV AND PUT IT INTO FLT LEVEL CHANGE MODE AND CHANGED THE SPD TO 280 KTS AS THE TURB SEEMED TO DISSIPATE TO LIGHT CHOP, OCCASIONAL SMOOTH.

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.