B737-700 captain reported encountering wake turbulence at FL310 from an opposite direction B747 at F...

Attributes
ACN	1409296
Time
Date	201612
Local Time Of Day	1201-1800
Place
Locale Reference	ZLA.ARTCC
State Reference	CA
Environment
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Aircraft 2
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 131
Events
Anomaly	Inflight Event / Encounter Wake Vortex Encounter

Narrative:

While enroute to phx at FL310 we encountered moderate wake turbulence for approximately 30 seconds to one minute from an opposite direction 747 directly above us at FL320. The winds aloft exactly paralleled our courses and after experiencing the wake turbulence for a few moments we decided to make a 30 degree turn to the left to fly out of the wake turbulence. We informed ATC of our turn. La center gave us no traffic report. I made a PA for flight attendants to take their seats. One F/a was forced to brace herself on the floor in the aisle. No injuries occurred. I made a passenger PA to explain what the turbulence was from.it seems that 1000 feet below separation between 747s and 737s is not adequate. ATC separation standards should be evaluated.

Original NASA ASRS Text

Title: B737-700 Captain reported encountering wake turbulence at FL310 from an opposite direction B747 at FL320. Reporter stated he would like to see the separation standards increased.

Narrative: While enroute to PHX at FL310 we encountered moderate wake turbulence for approximately 30 seconds to one minute from an opposite direction 747 directly above us at FL320. The winds aloft exactly paralleled our courses and after experiencing the wake turbulence for a few moments we decided to make a 30 degree turn to the left to fly out of the wake turbulence. We informed ATC of our turn. LA Center gave us no traffic report. I made a PA for Flight Attendants to take their seats. One F/A was forced to brace herself on the floor in the aisle. No injuries occurred. I made a passenger PA to explain what the turbulence was from.It seems that 1000 feet below separation between 747s and 737s is not adequate. ATC separation standards should be evaluated.

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.

B737-700 captain reported encountering wake turbulence at FL310 from an opposite direction B747 at FL320. Reporter stated he would like to see the separation standards increased.