A321
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
ATC Issue All Types; Inflight Event / Encounter Wake Vortex Encounter
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Environment - Non Weather Related; Procedure
Cleared via the RUGGD 2 RNAV SID. Maintain 230 KTS. Cleared to takeoff almost immediately behind a B757. Calm winds. We were heavy enough that 230 KTS was barely above green dot speed (min safe speed for an Airbus). Encountered up to moderate wake turbulence. Significant enough that I couldn't maintain altitude let alone climb and slightly descend at times to maintain a safe speed. No way to climb above it based the slow climb speed and being a heavy A321. Continued off and on until almost BUBBY waypoint. Eventually asked for a slight left upwind heading but it helped only a little.ATC clearing us to takeoff too close behind a B757. 230 KT demanded climb speed. We didn't demand a takeoff delay behind the B757 even though both aircraft are 'large'. We also didn't demand a higher climb speed.A B757 is still a hazardous aircraft to take off behind. Even our ADS-B system labels them as a 'high vortex' wake as opposed to simply 'large'. The FAA needs to re institute heavy wake separation behind B757s instead of cramming in more departures by deciding a large behind a 757 doesn't need any wake separation. I will be asking for at least 30 sec after liftoff or at least 1 minute after brake release when taking off behind a B757 from here on. The FAA should also be aware that an A321 is not the best performing aircraft.
Reporter stated action is needed to increase separation behind B757 aircraft.
A321 Captain reported encountering wake turbulence departing SLC in trail of a B757. Captain suggested that increased separation should be used behind the B757 type aircraft.