2 wake encounters within 2 mins results in 1 incident of loss of aircraft control.

Attributes
ACN	281474
Time
Date	199409
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 7000 msl bound upper : 9000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 14000 flight time type : 6000
ASRS Report	281474
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	inflight encounter other other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : regained aircraft control
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

While descending through 9000 ft MSL while receiving vectors for an approach to runway 9R in atl, we flew through wake turbulence. The aircraft, while on autoplt, rolled 15 degrees right, wing down and then immediately recovered. It was a sharp roll, the roll and recovery together took less than a second. Approach control advised that we were 8 mi behind a B767 that was also descending for an approach to runway 9R. It was level at 7000 ft at the time of my call (immediately after the recovery). 2 mins later while level at 7000 ft MSL, we again ran through wake turbulence. This time I was hand flying. My aircraft rolled 30 degrees right. I used full aileron deflection to the left for 5-8 seconds before recovery began. Approach control again advised that we were 8 mi behind a B767 who was behind a B757. About a yr ago, I sent one of these forms to you on the same subject. In it, I said that wake turbulence was encountered by me on an average of twice per month. This has not changed. I encounter a wake turbulence problem (though not as bad as the above) about twice a month. ATC always advises that the other aircraft is '5-8 mi ahead' or 'passed that area several mins ago.' other than 'more study of wake turbulence,' I do not have a recommendation. But I do wonder what flying behind the proposed 800-1000 seat airplanes will be like. 15 mins of separation?

Original NASA ASRS Text

Title: 2 WAKE ENCOUNTERS WITHIN 2 MINS RESULTS IN 1 INCIDENT OF LOSS OF ACFT CTL.

Narrative: WHILE DSNDING THROUGH 9000 FT MSL WHILE RECEIVING VECTORS FOR AN APCH TO RWY 9R IN ATL, WE FLEW THROUGH WAKE TURB. THE ACFT, WHILE ON AUTOPLT, ROLLED 15 DEGS R, WING DOWN AND THEN IMMEDIATELY RECOVERED. IT WAS A SHARP ROLL, THE ROLL AND RECOVERY TOGETHER TOOK LESS THAN A SECOND. APCH CTL ADVISED THAT WE WERE 8 MI BEHIND A B767 THAT WAS ALSO DSNDING FOR AN APCH TO RWY 9R. IT WAS LEVEL AT 7000 FT AT THE TIME OF MY CALL (IMMEDIATELY AFTER THE RECOVERY). 2 MINS LATER WHILE LEVEL AT 7000 FT MSL, WE AGAIN RAN THROUGH WAKE TURB. THIS TIME I WAS HAND FLYING. MY ACFT ROLLED 30 DEGS R. I USED FULL AILERON DEFLECTION TO THE L FOR 5-8 SECONDS BEFORE RECOVERY BEGAN. APCH CTL AGAIN ADVISED THAT WE WERE 8 MI BEHIND A B767 WHO WAS BEHIND A B757. ABOUT A YR AGO, I SENT ONE OF THESE FORMS TO YOU ON THE SAME SUBJECT. IN IT, I SAID THAT WAKE TURB WAS ENCOUNTERED BY ME ON AN AVERAGE OF TWICE PER MONTH. THIS HAS NOT CHANGED. I ENCOUNTER A WAKE TURB PROB (THOUGH NOT AS BAD AS THE ABOVE) ABOUT TWICE A MONTH. ATC ALWAYS ADVISES THAT THE OTHER ACFT IS '5-8 MI AHEAD' OR 'PASSED THAT AREA SEVERAL MINS AGO.' OTHER THAN 'MORE STUDY OF WAKE TURB,' I DO NOT HAVE A RECOMMENDATION. BUT I DO WONDER WHAT FLYING BEHIND THE PROPOSED 800-1000 SEAT AIRPLANES WILL BE LIKE. 15 MINS OF SEPARATION?

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.