B737-500 flight crew encounters wake turbulence while on sadde 6 arrival to lax.

Attributes
ACN	701786
Time
Date	200606
Local Time Of Day	1801 To 2400
Place
Locale Reference	intersection : bayst
State Reference	CA
Altitude	agl bound lower : 12000 agl single value : 39
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : sadde
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : sadde
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 200 flight time total : 12500 flight time type : 9000
ASRS Report	701786
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	inflight encounter : wake turbulence
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : exited adverse environment
Consequence	other
Supplementary
Problem Areas	Environmental Factor Airspace Structure Aircraft ATC Human Performance Flight Crew Human Performance
Primary Problem	Environmental Factor

Narrative:

Descending on the sadde arrival into lax approximately 10 mi north of bayst intersection; we were about 9 mi in trail of an air cargo B747 on the same arrival. As we leveled at 12000 ft we suddenly encountered the wake turbulence of the B747. Winds were light and variable at 12000 ft; but no mention from approach control that we were in trail of the heavy B747. There were other aircraft ahead of us and since approach did not inform us of the heavy I assumed the heavy B747 was one of the lead aircraft on the arrival; not in front. The aircraft buffeted then quickly rolled to about 30-35 degrees to the right; before we could recover control. The seatbelt sign was on; however; the 3 flight attendants were in the aft galley when we hit the wake. All 3 were thrown to the floor sustaining minor bumps and bruise-type injuries. After asking approach if we were following the heavy B747; we were told yes and if we like we could slow farther to 220 KTS for extra spacing. I called the cabin to ask if everyone was ok and the chief purser informed me that they were; however; hurt themselves when falling to the floor. Remainder of the flight was uneventful and once on the ground in lax the flight attendants did not see the need at that time to seek medical attention.

Original NASA ASRS Text

Title: B737-500 FLT CREW ENCOUNTERS WAKE TURB WHILE ON SADDE 6 ARR TO LAX.

Narrative: DSNDING ON THE SADDE ARR INTO LAX APPROX 10 MI N OF BAYST INTXN; WE WERE ABOUT 9 MI IN TRAIL OF AN AIR CARGO B747 ON THE SAME ARR. AS WE LEVELED AT 12000 FT WE SUDDENLY ENCOUNTERED THE WAKE TURB OF THE B747. WINDS WERE LIGHT AND VARIABLE AT 12000 FT; BUT NO MENTION FROM APCH CTL THAT WE WERE IN TRAIL OF THE HVY B747. THERE WERE OTHER ACFT AHEAD OF US AND SINCE APCH DID NOT INFORM US OF THE HVY I ASSUMED THE HVY B747 WAS ONE OF THE LEAD ACFT ON THE ARR; NOT IN FRONT. THE ACFT BUFFETED THEN QUICKLY ROLLED TO ABOUT 30-35 DEGS TO THE R; BEFORE WE COULD RECOVER CTL. THE SEATBELT SIGN WAS ON; HOWEVER; THE 3 FLT ATTENDANTS WERE IN THE AFT GALLEY WHEN WE HIT THE WAKE. ALL 3 WERE THROWN TO THE FLOOR SUSTAINING MINOR BUMPS AND BRUISE-TYPE INJURIES. AFTER ASKING APCH IF WE WERE FOLLOWING THE HVY B747; WE WERE TOLD YES AND IF WE LIKE WE COULD SLOW FARTHER TO 220 KTS FOR EXTRA SPACING. I CALLED THE CABIN TO ASK IF EVERYONE WAS OK AND THE CHIEF PURSER INFORMED ME THAT THEY WERE; HOWEVER; HURT THEMSELVES WHEN FALLING TO THE FLOOR. REMAINDER OF THE FLT WAS UNEVENTFUL AND ONCE ON THE GND IN LAX THE FLT ATTENDANTS DID NOT SEE THE NEED AT THAT TIME TO SEEK MEDICAL ATTN.

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.