B737-800
Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Requested ATC Assistance / Clarification
Environment - Non Weather Related; Procedure
This event was wake turbulence related. We were given a climb to FL360 by ATC (don't recall if ZDC or ZID Center) following in trail (approximately 9 miles) of another aircraft at FL360. Our optimum altitude was FL360; assigned speed of .75 Mach for spacing and autopilot engaged. At approximately FL355 we encountered wake turbulence which rolled our aircraft left; at which point the autopilot disengaged. The aircraft rolled to approximately 35-40 degrees angle of bank; at which point I was able to manually take control and returned to straight and level flight. We did get the aural 'bank angle' call out. I continued the climb to FL360 without any further incident. We reported the wake turbulence incident to ATC.Although the spacing looked good and winds negligible; perhaps we were too close to the aircraft ahead. I'll pay more attention to the aircraft in my vicinity.
I called ATC (Indianapolis Center I think) and told them of the incident. The Controller told us; 'a company plane; same type is in front of you.' We understood that to mean [another] B737. It was a very controlled/smooth recovery.
B737 flight crew reported encountering wake turbulence in trail of another B737 at FL355 while climbing to FL360.