B737-500 encountered B777 wake turbulence on runway 9R ord final.

Attributes
ACN	631813
Time
Date	200409
Day	Sun
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl single value : 5000
Environment
Flight Conditions	VMC
Aircraft 1
Controlling Facilities	tracon : c90.tracon tower : sfo.tower
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 9r
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : c90.tracon
Operator	common carrier : air carrier
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 150 flight time total : 1400 flight time type : 7000
ASRS Report	631813
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 160 flight time total : 6100 flight time type : 800
ASRS Report	631815
Events
Anomaly	inflight encounter : wake turbulence other anomaly
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : regained aircraft control
Supplementary
Problem Areas	Airspace Structure Environmental Factor Aircraft
Primary Problem	Aircraft

Narrative:

We were at 170 KTS, flaps 10 degrees, 5000 ft near pratt intersection, runway 94 ord, 6 mi in trail of a heavy B777. The autoplt was on in heading select. Then we got 2 small bumps indications of wake left over, but a second later we got a violent roll. I kicked the autoplt off and applied rudder and aileron to correct. We advised ATC and I asked the first officer to check in back. The first flight attendant was coming out of the forward lavatory when it happened and may have pulled a muscle holding on to the door, but said she was ok. It was the end of her trip and she went on home. I called ord TRACON and we both agreed we had good separation. We had already given the prepare for landing PA. I gained about 200 ft on recovery and slightly off the localizer. All passenger were ok. Supplemental information from acn 631815: rolling out on final to runway 9R in ord, we hit severe wake turbulence from a B777 6 mi ahead. Aircraft made 2 slight wing rocks and then rolled abruptly 80 degrees left. The captain disconnected the autoplt and recovered the aircraft.

Original NASA ASRS Text

Title: B737-500 ENCOUNTERED B777 WAKE TURB ON RWY 9R ORD FINAL.

Narrative: WE WERE AT 170 KTS, FLAPS 10 DEGS, 5000 FT NEAR PRATT INTXN, RWY 94 ORD, 6 MI IN TRAIL OF A HVY B777. THE AUTOPLT WAS ON IN HDG SELECT. THEN WE GOT 2 SMALL BUMPS INDICATIONS OF WAKE LEFT OVER, BUT A SECOND LATER WE GOT A VIOLENT ROLL. I KICKED THE AUTOPLT OFF AND APPLIED RUDDER AND AILERON TO CORRECT. WE ADVISED ATC AND I ASKED THE FO TO CHK IN BACK. THE FIRST FLT ATTENDANT WAS COMING OUT OF THE FORWARD LAVATORY WHEN IT HAPPENED AND MAY HAVE PULLED A MUSCLE HOLDING ON TO THE DOOR, BUT SAID SHE WAS OK. IT WAS THE END OF HER TRIP AND SHE WENT ON HOME. I CALLED ORD TRACON AND WE BOTH AGREED WE HAD GOOD SEPARATION. WE HAD ALREADY GIVEN THE PREPARE FOR LNDG PA. I GAINED ABOUT 200 FT ON RECOVERY AND SLIGHTLY OFF THE LOC. ALL PAX WERE OK. SUPPLEMENTAL INFO FROM ACN 631815: ROLLING OUT ON FINAL TO RWY 9R IN ORD, WE HIT SEVERE WAKE TURB FROM A B777 6 MI AHEAD. ACFT MADE 2 SLIGHT WING ROCKS AND THEN ROLLED ABRUPTLY 80 DEGS L. THE CAPT DISCONNECTED THE AUTOPLT AND RECOVERED THE ACFT.

Data retrieved from NASA's ASRS site as of July 2007 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.