Narrative:

Departed [runway] 25R at lax on summr 1 SID. When we checked in with socal departure; they instructed us to climb via the SID which was to FL230. It was night VMC. I saw traffic ahead of us and to our right when we climbed above fog layer. The traffic departed [runway] 24L simultaneously to our departure on [runway] 25R. I know this is a common practice at lax and ATC will provide separation in multiple ways down the line on the summr 1 SID. I continued to notice the traffic and eventually I noticed it on our TCAS. I believe I noticed it slightly below our altitude but not completely sure. We and the traffic were both climbing. At 9;800 feet; ATC (sct) asked us to level at 10;000 feet. We acknowledged the call; but immediately said unable due to the late instructions. ATC agreed and apologized. They indicated it was a late call from la center. We got to about 10;300 feet and then leveled off at 10;000 feet. I took over control; disconnected auto pilot and hand flew the aircraft to 10;000 feet. We then checked in with la center level at 10;000 feet just before waypoint darrk on SID. La center gave us no further clearance or instruction. Soon thereafter; we encountered moderate wake turbulence from a heavy A350. The aircraft was having difficulty maintain control on autopilot so first officer disconnected during the wake turbulence encounter. It was very clear we were way too close to the converging traffic and both of us met at waypoint darrk. I advised ATC of the wake encounter and concern with traffic separation. I asked immediately for a course offset. We were given a right turn heading off course. We then eventually received further claim clearance. We never were given a clearance to return to our route. We then asked ATC if they wanted us to return to course. Approximately 10 minutes after the heading clearance we got cleared to a waypoint on the serfr star for [destination airport].ATC did not seem to notice converging traffic on the summr SID. We complied with all proper instructions and clearances; but paid the price. First we had to take evasive action to maintain an altitude due to a late clearance. Then we got put way too close behind a heavy aircraft and encountered very strong moderate turbulence and again had to take over control of the aircraft. All of this should have been avoided if ATC would have noticed and provided proper lateral separation. I noticed the la center controller seemed overwhelmed. At this time of night that sector seems to take over a large area. The area is handling lax oceanic departures; northbound departures and arrivals. But the controller also handles approach clearances to numerous airports in the central coastal area of california. I think this work overload contributed to the issue we experienced.

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Original NASA ASRS Text

Title: EMB-175 Captain reported encountering wake turbulence at 10;000 feet after departing LAX in trail of an A350.

Narrative: Departed [Runway] 25R at LAX on SUMMR 1 SID. When we checked in with SOCAL Departure; they instructed us to climb via the SID which was to FL230. It was night VMC. I saw traffic ahead of us and to our right when we climbed above fog layer. The traffic departed [Runway] 24L simultaneously to our departure on [Runway] 25R. I know this is a common practice at LAX and ATC will provide separation in multiple ways down the line on the SUMMR 1 SID. I continued to notice the traffic and eventually I noticed it on our TCAS. I believe I noticed it slightly below our altitude but not completely sure. We and the traffic were both climbing. At 9;800 feet; ATC (SCT) asked us to level at 10;000 feet. We acknowledged the call; but immediately said unable due to the late instructions. ATC agreed and apologized. They indicated it was a late call from LA Center. We got to about 10;300 feet and then leveled off at 10;000 feet. I took over control; disconnected auto pilot and hand flew the aircraft to 10;000 feet. We then checked in with LA Center level at 10;000 feet just before waypoint DARRK on SID. LA Center gave us no further clearance or instruction. Soon thereafter; we encountered moderate wake turbulence from a heavy A350. The aircraft was having difficulty maintain control on autopilot so First Officer disconnected during the wake turbulence encounter. It was very clear we were way too close to the converging traffic and both of us met at waypoint DARRK. I advised ATC of the wake encounter and concern with traffic separation. I asked immediately for a course offset. We were given a right turn heading off course. We then eventually received further claim clearance. We never were given a clearance to return to our route. We then asked ATC if they wanted us to return to course. Approximately 10 minutes after the heading clearance we got cleared to a waypoint on the SERFR star for [destination airport].ATC did not seem to notice converging traffic on the SUMMR SID. We complied with all proper instructions and clearances; but paid the price. First we had to take evasive action to maintain an altitude due to a late clearance. Then we got put way too close behind a heavy aircraft and encountered very strong moderate turbulence and again had to take over control of the aircraft. All of this should have been avoided if ATC would have noticed and provided proper lateral separation. I noticed the LA Center Controller seemed overwhelmed. At this time of night that sector seems to take over a large area. The area is handling LAX Oceanic departures; northbound departures and arrivals. But the Controller also handles approach clearances to numerous airports in the central coastal area of California. I think this work overload contributed to the issue we experienced.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.