ZOA controller describes a situation where a smaller CL60 is following a B767 and encounters severe ...

Attributes
ACN	1215113
Time
Date	201411
Local Time Of Day	1801-2400
Place
Locale Reference	ZOA.ARTCC
State Reference	CA
Environment
Light	Night
Aircraft 1
Make Model Name	Light Transport
Flight Phase	Descent
Flight Plan	IFR
Aircraft 2
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 16
Events
Anomaly	Inflight Event / Encounter Weather / Turbulence Inflight Event / Encounter Loss Of Aircraft Control Inflight Event / Encounter Wake Vortex Encounter

Narrative:

Aircraft X (a CL60) was descending and crossing approx 20 degrees off the flight path and 10 miles behind aircraft Y (a boeing B767). Aircraft X reported severe turbulence at approx FL340 that included a 30 degree roll. Questioning aircraft in the vicinity and at the same altitude answered either 'smooth' or 'occasional light chop'. This leads me to believe the aircraft Y wake was likely the issue. While we are well versed with aircraft Y wake issues and separation requirements for aircraft that are slow/dirty; I was not aware such a wake issue may be a significant problem with the aircraft Y clean and in level flight at altitude and another aircraft approx 10 or more miles behind. I did not think; in this case; to issue a wake advisory or suspect such a serious issue might occur.increase awareness of aircraft Y wake issues related to aircraft clean and level and better determine an 'average' distance behind the aircraft that may be problematic.

Original NASA ASRS Text

Title: ZOA Controller describes a situation where a smaller CL60 is following a B767 and encounters severe turbulence. The B767 is 10 miles in front of the Challenger.

Narrative: Aircraft X (a CL60) was descending and crossing approx 20 degrees off the flight path and 10 miles behind Aircraft Y (a Boeing B767). Aircraft X reported severe turbulence at approx FL340 that included a 30 degree roll. Questioning aircraft in the vicinity and at the same altitude answered either 'smooth' or 'occasional light chop'. This leads me to believe the Aircraft Y wake was likely the issue. While we are well versed with Aircraft Y wake issues and separation requirements for aircraft that are slow/dirty; I was not aware such a wake issue may be a significant problem with the Aircraft Y clean and in level flight at altitude and another aircraft approx 10 or more miles behind. I did not think; in this case; to issue a wake advisory or suspect such a serious issue might occur.Increase awareness of Aircraft Y wake issues related to aircraft clean and level and better determine an 'average' distance behind the aircraft that may be problematic.

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.

ZOA controller describes a situation where a smaller CL60 is following a B767 and encounters severe turbulence. The B767 is 10 miles in front of the challenger.