Wake turbulence created by a B757.

Attributes
ACN	333237
Time
Date	199604
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : blh
State Reference	CA
Altitude	msl bound lower : 33000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : atp pilot : flight engineer pilot : commercial pilot : cfi
Experience	flight time last 90 days : 250 flight time total : 13000 flight time type : 5000
ASRS Report	333237
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	inflight encounter other other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course none taken : unable
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

We were just leveling off at our cruise altitude of 33000 ft when we experienced a 30 degree roll both left and right. Told center of the experience, and they said there was a B757 10 mi ahead at FL350. Greater separation is needed behind B757 during cruise. Callback conversation with reporter revealed the following information: reporter participated in the structured wake turbulence callback. Although reporter saw the preceding aircraft ahead of them on TCASII and they were 2000 ft lower, they were shocked by the jolt and bank induced by the wake of this leading aircraft. At that time they were not aware it was a B757 until ARTCC told them. With a separation of 10 mi, this flight crew would like that increased even greater. Duration of rolling bank encounter was estimated to be only 2 seconds with a roll of 30 degrees bank each way. Reporter did also estimate the jolt as close to severe.

Original NASA ASRS Text

Title: WAKE TURB CREATED BY A B757.

Narrative: WE WERE JUST LEVELING OFF AT OUR CRUISE ALT OF 33000 FT WHEN WE EXPERIENCED A 30 DEG ROLL BOTH L AND R. TOLD CTR OF THE EXPERIENCE, AND THEY SAID THERE WAS A B757 10 MI AHEAD AT FL350. GREATER SEPARATION IS NEEDED BEHIND B757 DURING CRUISE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR PARTICIPATED IN THE STRUCTURED WAKE TURB CALLBACK. ALTHOUGH RPTR SAW THE PRECEDING ACFT AHEAD OF THEM ON TCASII AND THEY WERE 2000 FT LOWER, THEY WERE SHOCKED BY THE JOLT AND BANK INDUCED BY THE WAKE OF THIS LEADING ACFT. AT THAT TIME THEY WERE NOT AWARE IT WAS A B757 UNTIL ARTCC TOLD THEM. WITH A SEPARATION OF 10 MI, THIS FLC WOULD LIKE THAT INCREASED EVEN GREATER. DURATION OF ROLLING BANK ENCOUNTER WAS ESTIMATED TO BE ONLY 2 SECONDS WITH A ROLL OF 30 DEGS BANK EACH WAY. RPTR DID ALSO ESTIMATE THE JOLT AS CLOSE TO SEVERE.

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.