A320 encountered wake turbulence after passing 1000 ft below opposite direction B747 traffic.

Attributes
ACN	656064
Time
Date	200504
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : bce.vortac
State Reference	UT
Altitude	msl single value : 32000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zlc.artcc
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zlc.artcc
Operator	common carrier : air carrier
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 16500 flight time type : 3100
ASRS Report	656064
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : airborne less severe inflight encounter : wake turbulence
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Airspace Structure Environmental Factor
Primary Problem	Airspace Structure

Narrative:

This incident occurred at FL320; 20 NM west of bce. WX was not a factor -- day; clear; smooth; unlimited visibility. Seat belt signs were off. Autoplt was on. Wind was directly on the nose -- 40K. No radio call from ARTCC was made concerning approaching traffic. I observed an aircraft at approximately 2 to 3 NM; approaching at our 12:30 position; at a slightly higher altitude. It was a B747. The B747 passed to our right; approximately 1 to 1.5 NM and at FL330 (1000 ft above our altitude). Approximately 2 mins later; we encountered the B747's wake turbulence. Our aircraft experienced approximately 2 to 3 seconds of moderate turbulence; and a 15 degree abrupt roll to the right. The autoplt remained engaged; and the aircraft returned to a normal; smooth flight condition. Two male passenger; standing near the rear galley; were knocked off balance. No known injuries were observed.

Original NASA ASRS Text

Title: A320 ENCOUNTERED WAKE TURB AFTER PASSING 1000 FT BELOW OPPOSITE DIRECTION B747 TFC.

Narrative: THIS INCIDENT OCCURRED AT FL320; 20 NM W OF BCE. WX WAS NOT A FACTOR -- DAY; CLR; SMOOTH; UNLIMITED VISIBILITY. SEAT BELT SIGNS WERE OFF. AUTOPLT WAS ON. WIND WAS DIRECTLY ON THE NOSE -- 40K. NO RADIO CALL FROM ARTCC WAS MADE CONCERNING APCHING TFC. I OBSERVED AN ACFT AT APPROX 2 TO 3 NM; APCHING AT OUR 12:30 POSITION; AT A SLIGHTLY HIGHER ALT. IT WAS A B747. THE B747 PASSED TO OUR R; APPROX 1 TO 1.5 NM AND AT FL330 (1000 FT ABOVE OUR ALT). APPROX 2 MINS LATER; WE ENCOUNTERED THE B747'S WAKE TURB. OUR ACFT EXPERIENCED APPROX 2 TO 3 SECONDS OF MODERATE TURB; AND A 15 DEG ABRUPT ROLL TO THE R. THE AUTOPLT REMAINED ENGAGED; AND THE ACFT RETURNED TO A NORMAL; SMOOTH FLT CONDITION. TWO MALE PAX; STANDING NEAR THE REAR GALLEY; WERE KNOCKED OFF BALANCE. NO KNOWN INJURIES WERE OBSERVED.

Data retrieved from NASA's ASRS site as of January 2009 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.