Date: 202108
Local time of day: 1801-2400
Location: ATL.Airport, GA
Light: Night
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Climb
Airspace: Class B ATL
ATC / advisory: TRACON A80
Second aircraft: B757 Undifferentiated or Other Model
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Contributing factors: Procedure; Human Factors
Primary problem: Ambiguous

Narrative: We were cleared for takeoff by ATL Tower immediately behind a 757. As the 757 was not calling himself a heavy; I guess no wake turbulence separation was required. After takeoff; at about 1;000 feet AGL; we encountered a rolling motion to the left due to the 757 wake turbulence. I applied right aileron and the aircraft rolled wings level. I followed the magenta line on the NAV display; and we hit the 757 turbulence again. The aircraft rolled left; I applied right aileron but this time the aircraft continued to roll left. With full aileron input; the aircraft slowly came back to level flight. The 757 was climbing above us to our left. I checked the wind display on the NAV display (ND) and the winds were calm; so no help to move the wake turbulence out of the departure ground track. For safety of flight reasons; I decided to offset slightly to the right of track to get into clean air. At this point we were flying the 082 heading away from the south runway complex. It was a clear night and no aircraft were south of us. Once in clean air; I turned direct to RONII; but my ground track was slightly right of the magenta line on the NAV display. Now that we were safely flying; I was asking the First Officer (F/O) to let Departure Control know we were off track when Departure Control called us and asked if we knew we were south of course. We told him we had offset our track to avoid the wake turbulence we encountered; he replied that no deviation was allowed on the departure and gave us a phone number to call about a potential pilot deviation.If indeed the 757 was not a heavy; then no procedures were violated in having us take off immediately behind him. Had there been some wind in the climb out we probably never would have encountered the wake turbulence. As it was; I had the choice of fighting the wake turbulence and staying on the ground track or offsetting. Since I had one encounter that required full aileron input; and then was slow to recover; staying in the turbulence was not an option. The 757 was left of us. Had I attempted to offset to his left (north of track) I would have had to cross both turbulence vortices. Moving slightly to the right was the only option I could safely make.


Second narrative: Climbing on the VARNM Departure off [Runway] 8R; we experienced moderate wake turbulence from the (other carrier) 757 ahead. Captain was Pilot Flying and decided it would be the safest course of action to deviate right of course; without notifying Departure. He deviated around two degrees right and we were immediately questioned by Departure. I responded to Departure; 'Yes; we are deviating right for wake turbulence.' He said we could not do that and to contact this phone number.


Synopsis: B737-700 flight crew reported encountering wake turbulence departing ATL in trail of a B757.