B737-700 flight crew reported wake turbulence encounter during arrival to lax in 12-mile trail that ...

Narrative:

On the sadde 6 arrival in lax; we were given descent to 7;000 ft approximately 10 NM west of smo VOR by socal approach. At approximately 8;500 ft we encountered moderate turbulence from a preceding heavy aircraft. Roll change of approximately 30 degrees was experienced almost immediately and I disconnected the autopilot began a level off to stay out of the wake turbulence. Captain advised approach control of the level off at 8;400 ft due to wake turbulence; but the controller was saturated with a lot of calls. He did not acknowledge our transmission. Later the controller advised us; we need to tell him of level off and we need to keep coming down due to other traffic at that altitude. After additional spacing with preceding traffic; we landed without incident. The controller had us 12 miles behind heavy traffic. This should have been more than enough; but this day; it was not enough space to keep us out of the wake zone. This is a busy time for both the pilots and controllers; but perhaps further distances are needed at times to prevent such events.

Original NASA ASRS Text

Title: B737-700 flight crew reported wake turbulence encounter during arrival to LAX in 12-mile trail that resulted in sudden 30-degree roll. Crew paused their descent and were subsequently criticized by ATC.

Narrative: On the SADDE 6 Arrival in LAX; we were given descent to 7;000 FT approximately 10 NM west of SMO VOR by SOCAL Approach. At approximately 8;500 FT we encountered moderate turbulence from a preceding heavy aircraft. Roll change of approximately 30 degrees was experienced almost immediately and I disconnected the autopilot began a level off to stay out of the wake turbulence. Captain advised Approach Control of the level off at 8;400 FT due to wake turbulence; but the Controller was saturated with a lot of calls. He did not acknowledge our transmission. Later the Controller advised us; we need to tell him of level off and we need to keep coming down due to other traffic at that altitude. After additional spacing with preceding traffic; we landed without incident. The Controller had us 12 miles behind heavy traffic. This should have been more than enough; but this day; it was not enough space to keep us out of the wake zone. This is a busy time for both the pilots and controllers; but perhaps further distances are needed at times to prevent such events.

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.

Attributes
ACN	1200266
Time
Date	201409
Local Time Of Day	0601-1200
Place
Locale Reference	LAX.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR SADDE6
Flight Plan	IFR
Aircraft 2
Make Model Name	Heavy Transport
Flight Phase	Descent
Person 1
Function	Pilot Flying First Officer
Experience	Flight Crew Last 90 Days 214
Person 2
Function	Captain Pilot Not Flying
Experience	Flight Crew Last 90 Days 202
Events
Anomaly	ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Wake Vortex Encounter

B737-700 flight crew reported wake turbulence encounter during arrival to lax in 12-mile trail that resulted in sudden 30-degree roll. Crew paused their descent and were subsequently criticized by ATC.