A B767-300 encounters strong wake turbulence at cruise altitude in ZLA airspace.

Attributes
ACN	406105
Time
Date	199806
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : pke
State Reference	CA
Altitude	msl bound lower : 37000 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	common carrier : air carrier
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 1000
ASRS Report	406105
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	inflight encounter other other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

B767-300 10 mi in trail of B777 at FL370, wind 80 KTS on tail. Wake turbulence created temporary loss of control -- uncommanded roll left. Unable to counter with full right aileron. Reached 45 degree angle of bank before turbulence subsided allowing flight controls to be effective again and recover. Callback conversation with reporter revealed the following information: the reporter participated in the structured wake turbulence callback program. The reporter stated that the wake was smooth, with little loss of altitude (100 ft) and a total displacement off course of 300 ft. What they could not control was the bank angle. Aircraft rotated smoothly to 45 degrees of bank before the aileron control was effective enough to roll the aircraft back level. Aircraft was being manually flown so maximum aileron could be applied. Preceding aircraft was a B777, 10 mi ahead of this aircraft.

Original NASA ASRS Text

Title: A B767-300 ENCOUNTERS STRONG WAKE TURB AT CRUISE ALT IN ZLA AIRSPACE.

Narrative: B767-300 10 MI IN TRAIL OF B777 AT FL370, WIND 80 KTS ON TAIL. WAKE TURB CREATED TEMPORARY LOSS OF CTL -- UNCOMMANDED ROLL L. UNABLE TO COUNTER WITH FULL R AILERON. REACHED 45 DEG ANGLE OF BANK BEFORE TURB SUBSIDED ALLOWING FLT CTLS TO BE EFFECTIVE AGAIN AND RECOVER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR PARTICIPATED IN THE STRUCTURED WAKE TURB CALLBACK PROGRAM. THE RPTR STATED THAT THE WAKE WAS SMOOTH, WITH LITTLE LOSS OF ALT (100 FT) AND A TOTAL DISPLACEMENT OFF COURSE OF 300 FT. WHAT THEY COULD NOT CTL WAS THE BANK ANGLE. ACFT ROTATED SMOOTHLY TO 45 DEGS OF BANK BEFORE THE AILERON CTL WAS EFFECTIVE ENOUGH TO ROLL THE ACFT BACK LEVEL. ACFT WAS BEING MANUALLY FLOWN SO MAX AILERON COULD BE APPLIED. PRECEDING ACFT WAS A B777, 10 MI AHEAD OF THIS ACFT.

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.