B767-300 and 300 ER
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 150; Flight Crew Total 14000; Flight Crew Type 2500
Inflight Event / Encounter Wake Vortex Encounter
General None Reported / Taken
Environment - Non Weather Related
While level at 7;000 FT; we encountered wake turbulence. We were level at 7;000 FT at a speed of 250 KIAS; approximately 8 miles behind a B757 also level at 7;000 FT. The autopilot was engaged as we encountered the wake turbulence. The aircraft began to roll right reaching a maximum estimated  bank angle of approximately 15 degrees. At some point in the right bank; the stickshaker activated momentarily (less than a second). I disengaged the autopilot and rolled the wings level using ailerons alone; the aircraft responded immediately to aileron input. The entire event lasted about 3 seconds. No parameters or limits were exceeded and no altitude was lost.
[Narrative 2 contained no additional information]
A B767-300 flight crew reported encountering wake turbulence from a preceding B757 that was eight miles ahead.