Narrative:

This is a wake turbulence/vortex encounter report. The 2ND of two encounters resulted in minor injuries to flight attendants and some passenger who declined to be interviewed further. One flight attendant hurt her arm falling against bulkhead. At the start of descent from FL270 while flying 250 KTS assigned in smooth air; the aircraft was hit by a very tight strong vortex. The seat belt sign was off and I (captain) cycled it on and off several times while the first officer went for the PA microphone. The aircraft was released from the vortex fairly quickly. We were 14 miles in trail of a 747. The sign remained on while the first officer made a firm PA regarding the nature of turbulence. He indicated that we would by trying to stay clear of them but that another encounter was possible. ATC was advised and they indicated that the 747 was 14 miles ahead. There was a bit of disbelief in his voice. We were well below the descent path into gramm intersection (civet five) and we were also slow; so I increased descent and turned upwind a little. About 2 minutes after the first encounter; we were hit again. This time the aircraft was upset a full 30 degrees to the right in a very short span of time. I clicked off both a/P and a/T and brought the aircraft level and stopped descent for a short while. The first officer advocated that we stay high from this point on which we did. ATC was advised again and we told them we needed left (upwind/track) deviation and relief from all at or below restrs on the arrival. ATC granted this. ATC then slowed us further to 230 KTS and sequenced a 737 between us and the 747. We never heard a complaint from this 737; but another 737 behind us also complained about the wake turbulence. No further encounters occurred and a normal landing at lax was conducted. I was out of the cockpit as soon as checklists were completed and faced every passenger on the way out. I was told of no passenger injuries as passenger deplaned. One passenger pointed to another passenger and said 'she was hurt;' but the first passenger just continued off the aircraft. In post flight interview with attendants I was told that one lady who had crutches was slow to get out of the bathroom and was thus knocked down in the encounter. Several people were up; despite the first encounter and the sign being on. The flight attendant attempted to assist her and keep her from falling; but fell herself as the roll moment was too great. The flight attendant hit her arm in the fall.

Related reports:

Google
 

Original NASA ASRS Text

Title: B737 FLT CREW RPTS ENCOUNTERING WAKE TURBULENCE FROM A PRECEDING B747 WHILE DESCENDING INTO LAX ON THE CIVET 5 AT FL260.

Narrative: THIS IS A WAKE TURBULENCE/VORTEX ENCOUNTER RPT. THE 2ND OF TWO ENCOUNTERS RESULTED IN MINOR INJURIES TO FLIGHT ATTENDANTS AND SOME PAX WHO DECLINED TO BE INTERVIEWED FURTHER. ONE FLT ATTENDANT HURT HER ARM FALLING AGAINST BULKHEAD. AT THE START OF DESCENT FROM FL270 WHILE FLYING 250 KTS ASSIGNED IN SMOOTH AIR; THE ACFT WAS HIT BY A VERY TIGHT STRONG VORTEX. THE SEAT BELT SIGN WAS OFF AND I (CAPT) CYCLED IT ON AND OFF SEVERAL TIMES WHILE THE FO WENT FOR THE PA MIKE. THE ACFT WAS RELEASED FROM THE VORTEX FAIRLY QUICKLY. WE WERE 14 MILES IN TRAIL OF A 747. THE SIGN REMAINED ON WHILE THE FO MADE A FIRM PA REGARDING THE NATURE OF TURBULENCE. HE INDICATED THAT WE WOULD BY TRYING TO STAY CLEAR OF THEM BUT THAT ANOTHER ENCOUNTER WAS POSSIBLE. ATC WAS ADVISED AND THEY INDICATED THAT THE 747 WAS 14 MILES AHEAD. THERE WAS A BIT OF DISBELIEF IN HIS VOICE. WE WERE WELL BELOW THE DESCENT PATH INTO GRAMM INTXN (CIVET FIVE) AND WE WERE ALSO SLOW; SO I INCREASED DESCENT AND TURNED UPWIND A LITTLE. ABOUT 2 MINUTES AFTER THE FIRST ENCOUNTER; WE WERE HIT AGAIN. THIS TIME THE ACFT WAS UPSET A FULL 30 DEGREES TO THE R IN A VERY SHORT SPAN OF TIME. I CLICKED OFF BOTH A/P AND A/T AND BROUGHT THE ACFT LEVEL AND STOPPED DESCENT FOR A SHORT WHILE. THE FO ADVOCATED THAT WE STAY HIGH FROM THIS POINT ON WHICH WE DID. ATC WAS ADVISED AGAIN AND WE TOLD THEM WE NEEDED LEFT (UPWIND/TRACK) DEV AND RELIEF FROM ALL AT OR BELOW RESTRS ON THE ARR. ATC GRANTED THIS. ATC THEN SLOWED US FURTHER TO 230 KTS AND SEQUENCED A 737 BETWEEN US AND THE 747. WE NEVER HEARD A COMPLAINT FROM THIS 737; BUT ANOTHER 737 BEHIND US ALSO COMPLAINED ABOUT THE WAKE TURBULENCE. NO FURTHER ENCOUNTERS OCCURRED AND A NORMAL LNDG AT LAX WAS CONDUCTED. I WAS OUT OF THE COCKPIT AS SOON AS CHECKLISTS WERE COMPLETED AND FACED EVERY PAX ON THE WAY OUT. I WAS TOLD OF NO PAX INJURIES AS PAX DEPLANED. ONE PAX POINTED TO ANOTHER PAX AND SAID 'SHE WAS HURT;' BUT THE FIRST PAX JUST CONTINUED OFF THE ACFT. IN POST FLIGHT INTERVIEW WITH ATTENDANTS I WAS TOLD THAT ONE LADY WHO HAD CRUTCHES WAS SLOW TO GET OUT OF THE BATHROOM AND WAS THUS KNOCKED DOWN IN THE ENCOUNTER. SEVERAL PEOPLE WERE UP; DESPITE THE FIRST ENCOUNTER AND THE SIGN BEING ON. THE FLT ATTENDANT ATTEMPTED TO ASSIST HER AND KEEP HER FROM FALLING; BUT FELL HERSELF AS THE ROLL MOMENT WAS TOO GREAT. THE FLT ATTENDANT HIT HER ARM IN THE FALL.

Data retrieved from NASA's ASRS site as of January 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.