B737-800
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Loss Of Aircraft Control
Air Traffic Control Issued New Clearance; Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification
Environment - Non Weather Related; Procedure
We were at FL320 on the HLYWD arrival into LAX; and we had been given a vector off course for spacing. Upon rejoining the arrival we were given slower speeds until we actually saw an aircraft 5 nm in front of us. We were then assigned a speed of 250 kts indicated; then descend to FL240; followed by a clearance to descend via the arrival. I was concerned as we started our descent as we were clearly descending at a higher rate than the aircraft ahead of us and would be flying through their flight path at a close proximity plus winds at altitude were approximately 110kts. Suddenly our airplane began a roll to the right; I would estimate 20-25 degrees of bank; then it began rolling to the left at least 30 degrees of bank if not more and the autopilot disconnected itself. We were having an upset due to wake from the aircraft ahead of us so the Captain quickly recovered and I advised ATC what was happening and that we needed something different. They approved an offset to our course; and then advised the aircraft ahead was a B777. 5nm is inadequate spacing between a heavy aircraft and others. Fortunately we recovered well and landed safely. 99 percent of the time our folks in ATC do an absolutely outstanding job; and we couldn't do this without them! This event is unusual; but highlights an opportunity we can improve.I would also like to see better communication from ATC and a better understanding of the safety ramifications of wake turbulence - I frequently get the impression that they don't understand this risk adequately. I want to know if I'm in trail of a heavy aircraft! Sooner than later! It matters; it changes my expectations and I'm not consistently getting this information. I recommend more spacing; more and consistent communication about heavy aircraft ahead; and if I need to be vectored for spacing then let's address speed at the same time so I'm not constantly changing my configuration when I need to focus on flying.
B737 First Officer reported encountering wake turbulence on descent into LAX in trail of a B777.