B737-800
Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Took Evasive Action
Environment - Non Weather Related; Procedure
We experienced a severe rolling motion due to wake turbulence behind a B-757 on takeoff from DFW 36R. I was cleared for takeoff immediately after tower cleared the B-757 for takeoff. I started my takeoff roll about 1:25 after the B-757. I encountered the wake turbulence approximately 250-300 AGL and had to use approximately 60 degrees of aileron to counter the wake upset. This is the first time I did not use a two minute separation behind a B-757. I notified tower of the encounter with the wake turbulence. I will now accept only a 2 minute interval behind B-757 per my option from AIM 7-3-9 and Part 1; 5..7.2.B.
Reporter stated he sometimes feels pressure from Tower to waive the two minute separation option.
B737-800 Captain reported experiencing a 'severe rolling motion' shortly after takeoff from DFW from wake turbulence in trail of a B757.