B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 136; Flight Crew Total 11924; Flight Crew Type 9215
Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Environment - Non Weather Related; Procedure; Human Factors
On a visual approach to 27L ORD. Encountered intermittent wake from preceding aircraft. Around GRABL airspeed dropped off by approximately 20 kts. During recovery to assigned 250 kts; ATC asked us not to slow until advised (mentioned this as we were recovering through approximately 234 kts). We acknowledged and continued to landing with a stable approach. We did not slow the speed intentionally; but since ATC mentioned it; I felt an explanation was warranted. Autopilot was engaged initially; but was disengaged to recover airspeed and continue visual approach and landing.
B737NG Captain reported slowing below assigned airspeed after encountering wake turbulence on arrival into ORD.