B737-700
Flight Crew Last 90 Days 185
Communication Breakdown; Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Took Evasive Action
Human Factors; Environment - Non Weather Related
While on the ERLIN 9 RNAV Arrival into Atlanta; encountered three wake turbulence events after which I asked if we were following a Heavy. ATC responded that we were preceded by a B757. After passing NOFIV and clearance to a lower altitude I asked the pilot flying to shallow the descent to avoid further wake encounter. Once the B757 turned base we were able to keep traffic in sight and in our base turn with a speed assignment of 170 KTS; we were asked to follow the B757 to the airport but maintain present heading and plan a turn to join final. ATC provided heading to join final and cleared us for a visual approach call the Tower at AJAAY. At this point we continued to slow and configure due to being above glide slope. Before reaching AJAAY; Approach asked our speed and instructed aircraft behind us to slow. I believe that ATC was planning for us to keep our 170 KTS until reaching the marker as stated in Safety Alert [bulletin]. Our clearance was cleared visual approach with no stated speed to the marker. Believe I may have become too conservative in my approach to wake avoidance. With traffic volume into ATL should have done a better job with ATC communication.
A B737-700 pilot reported deviating from ATC assigned speed to increase spacing behind a B757 that was causing some wake turbulence.