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The crew of a B737-700 encounters wake turbulence from a preceding B747 while in descent into lax from the east. A flight attendant was injured.
| Attributes | |
| ACN | 700308 |
| Time | |
| Date | 200606 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : lax.vortac |
| State Reference | CA |
| Altitude | msl single value : 26000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-700 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : vacating altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zla.artcc |
| Make Model Name | B747 Undifferentiated or Other Model |
| Flight Phase | descent : vacating altitude |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 270 flight time total : 10000 |
| ASRS Report | 700308 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | inflight encounter : wake turbulence |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : provided flight assist flight crew : regained aircraft control |
| Consequence | other |
| Supplementary | |
| Problem Areas | Airspace Structure Environmental Factor |
| Primary Problem | Airspace Structure |
Narrative:
While on descent into lax; out of FL260 to FL240 we encountered what started as light-moderate chop. This was followed by an uncommanded roll to the left of approximately 25-30 degrees of bank with abrupt sink/climb rate of 800 FPM; characteristic of wake turbulence. I immediately disconnected the autoplt and initiated a roll in the opposite direction; using 70-80% opposite aileron. The captain informed ATC of the severe wake turbulence and requested a turn to avoid further disruptions. ATC informed us we were in trail of a B747. TCAS shown the B747 15-20 mi ahead and approximately 3000 ft below us descending. Once we were stabilized and offset from the B747's course; the captain called to check the status of our flight attendants. The 'a' flight attendant informed him that everyone seemed ok but our 'B' attendant had taken a hard fall in the aft galley and he was having pain in his side. We coordination with los angeles operations to have EMS standing by. Customer service representatives were also in the jetway upon arrival. The aircraft was removed from service for inspection due to the severe turbulence report. Although ATC had given us adequate separation (15-20 mi) from the B747; in the future I will certainly pay closer attention to the type of traffic to be followed; no matter how far above or behind we are.
Original NASA ASRS Text
Title: THE CREW OF A B737-700 ENCOUNTERS WAKE TURB FROM A PRECEDING B747 WHILE IN DSCNT INTO LAX FROM THE E. A FLT ATTENDANT WAS INJURED.
Narrative: WHILE ON DSCNT INTO LAX; OUT OF FL260 TO FL240 WE ENCOUNTERED WHAT STARTED AS LIGHT-MODERATE CHOP. THIS WAS FOLLOWED BY AN UNCOMMANDED ROLL TO THE L OF APPROX 25-30 DEGS OF BANK WITH ABRUPT SINK/CLB RATE OF 800 FPM; CHARACTERISTIC OF WAKE TURB. I IMMEDIATELY DISCONNECTED THE AUTOPLT AND INITIATED A ROLL IN THE OPPOSITE DIRECTION; USING 70-80% OPPOSITE AILERON. THE CAPT INFORMED ATC OF THE SEVERE WAKE TURB AND REQUESTED A TURN TO AVOID FURTHER DISRUPTIONS. ATC INFORMED US WE WERE IN TRAIL OF A B747. TCAS SHOWN THE B747 15-20 MI AHEAD AND APPROX 3000 FT BELOW US DSNDING. ONCE WE WERE STABILIZED AND OFFSET FROM THE B747'S COURSE; THE CAPT CALLED TO CHK THE STATUS OF OUR FLT ATTENDANTS. THE 'A' FLT ATTENDANT INFORMED HIM THAT EVERYONE SEEMED OK BUT OUR 'B' ATTENDANT HAD TAKEN A HARD FALL IN THE AFT GALLEY AND HE WAS HAVING PAIN IN HIS SIDE. WE COORD WITH LOS ANGELES OPS TO HAVE EMS STANDING BY. CUSTOMER SVC REPRESENTATIVES WERE ALSO IN THE JETWAY UPON ARR. THE ACFT WAS REMOVED FROM SVC FOR INSPECTION DUE TO THE SEVERE TURB RPT. ALTHOUGH ATC HAD GIVEN US ADEQUATE SEPARATION (15-20 MI) FROM THE B747; IN THE FUTURE I WILL CERTAINLY PAY CLOSER ATTN TO THE TYPE OF TFC TO BE FOLLOWED; NO MATTER HOW FAR ABOVE OR BEHIND WE ARE.
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.