Widebody Transport
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 8
Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Airspace Structure; Procedure; Human Factors
Aircraft X descending on BRIXX arrival for SJC to 12;000. Aircraft Y descending on BDEGA for SFO to 11;000. Aircraft Y was advised of traffic and cautioned for wake turbulence on Aircraft X restricted above descending to 12;000. Aircraft Y requested a vector to get away from wake. I turned to 160. Shortly after; I observed Aircraft X descending out of 11;800 and advised it should be leveling at 12;000. Aircraft X advised that's not how he understood his clearance. Brasher statement issued.Remove MEA altitudes on BRIXX arrival after BRIXX to reduce confusion with descend via altitudes.
NorCal TRACON Controller reported that an aircraft descended below assigned altitude causing a loss of separation with a heavy aircraft.