B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 229; Flight Crew Type 14000
Deviation - Altitude Excursion From Assigned Altitude; Inflight Event / Encounter Wake Vortex Encounter
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action; Flight Crew Returned To Clearance
Environment - Non Weather Related; Procedure
We were in cruise at FL360 when the aircraft entered the wake of another 737; later reported as 8 miles ahead. The aircraft initially rolled strongly to the left at a rate the autopilot could not counter. I disconnected the autopilot; and rolled back to the right to level flight. There was a large amount of buffeting; and then we had lost 200 to 300 ft in the initial roll. I began to pitch up to return to FL360; as we entered an equally strong roll to the right. I abandoned the effort to climb back to altitude; and tried to get us back to level flight. We lost an additional 200 to 300 ft of altitude in the second roll. Center called us to verify our assigned altitude; and the FO reported the wake turbulence encounter; requesting a lower altitude to escape it. Center immediately gave us clearance to FL350; and a vector off course to escape the wake. This was one of the strongest wakes I have ever encountered. We were perfectly aligned behind the preceding 737; with the wind also perfectly aligned with our flight path. Once we entered the wake; we were going to stay in it until we changed course. In the future I will pay more attention to the direction of the winds aloft when considering the effect of wake turbulence.
[Report narrative contained no additional information.]
B737 flight crew reported a wake turbulence encounter at FL360 in 8-mile trail of another B737 that resulted in loss of 500-600 feet of altitude.