Date: 201706
Local time of day: 0601-1200
Location: SCT.TRACON, CA
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E SCT
ATC / advisory: TRACON SCT
Second aircraft: Heavy Transport
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Workload; Distraction
Second reporter function: Pilot Not Flying; Captain
Anomaly: Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Wake Vortex Encounter
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Environment - Non Weather Related; Procedure; Human Factors
Primary problem: Human Factors

Narrative: I was the pilot flying. We were given a descend via the arrival instruction except to maintain .78 Mach. This was then changed to cross a fix at or below 18000'; maintain speed with caution following a heavy. I changed the constraint at the fix to 17000' to ensure the crossing. The whole way [we were] getting into and out of the wake from the heavy in front of us. To ease out of the wake and to comply with altitude; I switched from managed to vertical speed and we crossed just below FL180 as requested.The next fix was 7.2 miles away with a hard altitude of 17000'; we encountered more wake with roll and I used the VSI to get out of it again. We were out of the wake. I missed not getting out of vertical speed mode and sending it to manage. I recognized this just before crossing the fix four hundred feet low and started to correct. ATC issued [descend to] 14;000' at the same time.I set 14;000' and continued to descend with no further issue.In dealing with the change in the arrival to go fast & cross at a different altitude; while dealing with the wake of the previous aircraft I was put into the yellow. Hindsight says I should have done the obvious by asking for some relief and to verbalize (I can't remember if I did or not but I definitely will next time) my exiting managed mode and going to vertical speed.


Second narrative: While descending via the HLYWD 1 arrival we were given a clearance to cross AVATR intersection at or below FL180; 1;000 feet lower than the lowest altitude constraint for that intersection. ATC cautioned us to possible wake turbulence from a [heavy] ahead. We encountered the wake turbulence multiple times with significant intensity. As we approached DAAAY intersection ATC gave us a friendly reminder that DAAAY has an altitude restriction of 17;000 feet and cleared us to descend to 14;000 feet. I noticed that we were about 400 feet low for the DAAAY constraint. No loss of separation occurred.While being distracted by the intense wake turbulence; I failed to notice that the First Officer took us out of managed descent by using vertical speed mode to control the descent. Using vertical speed was inappropriate on an RNAV arrival and a better course of action may have been a request for a heading away from the turbulence.


Synopsis: A321 flight crew reported overshooting a crossing restriction after being distracted by wake turbulence and changes to the ATC clearance.