A319
Flight Crew Air Transport Pilot (ATP)
Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Wake Vortex Encounter
Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action
Environment - Non Weather Related; Procedure
During descent on the WATSN2 RNAV Arrival into ORD and cleared to descend to and maintain 12;000 feet at HULLS; at about 14;000 feet on the autopilot we encountered wake turbulence from the aircraft ahead of us. We rolled left and right in excess of 30 degrees before flying out of it. We enquired about the type of aircraft in front of us--it was a B-737. Shortly thereafter we re-entered its wake with the same result and immediately requested a slight deviation 10 degrees to the right. The Approach Controller stated he was unable to approve that due to departure traffic from O'Hare. To avoid entering the wake a third time; I disconnected the autopilot and hand flew the aircraft slightly above and to the right of the RNAV path. This resulted in the failure to be level at HULLS at 12;000 feet; crossing it instead about 500 feet high. Once level I re-engaged the autopilot and resumed the WATSN2 Arrival. No further wake encounters occurred.
[Report Narrative Contained No Additional Information.]
A319 flight crew reported encountering wake turbulence in trail of a B737 on the WATSN2 arrival to ORD that resulted in rolls left and right in excess of 30 degrees.