Narrative:

While on left downwind for runway 27L at atl and descending through 7000 ft, experienced severe wake turbulence. We were 5 mi in trail of a B767-300 being vectored for an approach. No warnings were given about the aircraft ahead. Experienced 2 uncommanded rolls, one in each direction, of between 20 degrees and 30 degrees. Total duration of incident was approximately 15 seconds. This sort of occurrence is common in and out of atl. Controllers there are constantly putting us into the path of heavier equipment. Callback conversation with reporter revealed the following information: the reporter was the flying first officer on an EMB120 that was descending through clouds at 7000 ft when the aircraft had a violent wake encounter. The first officer said that the crew saw an aircraft on their TCASII display that showed 3 mi ahead and descending below them. The approach controller had not mentioned the traffic to them and they assumed that the display was showing another commuter aircraft. As they felt the initial nibbles of the wake, the first officer said that he gripped the control tightly and prepared to disconnect the autoplt. The aircraft suddenly rolled to the right reaching 30 degrees of bank even though the first officer put in full left rudder and aileron. The aircraft stopped the roll at that point, hesitated then slowly rolled to a wings level attitude. He relaxed the control inputs, he said, but a few seconds later the aircraft rolled just as violently to the left again with full rudder and aileron to counter. This time the roll seemed to stop at 20 degrees then very slowly increase toward 30 degrees, but did not quite make it that far. The aircraft again hesitated at the maximum bank angle and then slowly recovered. After this it was again smooth. The flight crew reported the encounter to the approach controller and asked what kind of aircraft it was. The controller, allegedly, would only respond that the aircraft was 5 mi ahead of them and they had legal separation. The controller later assigned them a parallel runway instead of requiring them to follow the, as yet unknown, traffic. As the crew broke out of the clouds on final approach they could see that the other aircraft was a B767-300. It was new and had a large identify logo on the aircraft. The reporter said that he has had unusual attitude recovery training at his airline and he feels that it was very helpful during this encounter.

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Original NASA ASRS Text

Title: AN ACR E120 FLC HIT THE WAKE OF A B767 WHILE ON DOWNWIND. THE APCH CTLR DID NOT GIVE THE FLC PRIOR NOTICE OF WHAT ACFT THEY WERE FOLLOWING AND, THE RPTR ALLEGES, WOULD NOT TELL HIM THE TYPE AFTER THE ENCOUNTER.

Narrative: WHILE ON L DOWNWIND FOR RWY 27L AT ATL AND DSNDING THROUGH 7000 FT, EXPERIENCED SEVERE WAKE TURB. WE WERE 5 MI IN TRAIL OF A B767-300 BEING VECTORED FOR AN APCH. NO WARNINGS WERE GIVEN ABOUT THE ACFT AHEAD. EXPERIENCED 2 UNCOMMANDED ROLLS, ONE IN EACH DIRECTION, OF BTWN 20 DEGS AND 30 DEGS. TOTAL DURATION OF INCIDENT WAS APPROX 15 SECONDS. THIS SORT OF OCCURRENCE IS COMMON IN AND OUT OF ATL. CTLRS THERE ARE CONSTANTLY PUTTING US INTO THE PATH OF HEAVIER EQUIP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS THE FLYING FO ON AN EMB120 THAT WAS DSNDING THROUGH CLOUDS AT 7000 FT WHEN THE ACFT HAD A VIOLENT WAKE ENCOUNTER. THE FO SAID THAT THE CREW SAW AN ACFT ON THEIR TCASII DISPLAY THAT SHOWED 3 MI AHEAD AND DSNDING BELOW THEM. THE APCH CTLR HAD NOT MENTIONED THE TFC TO THEM AND THEY ASSUMED THAT THE DISPLAY WAS SHOWING ANOTHER COMMUTER ACFT. AS THEY FELT THE INITIAL NIBBLES OF THE WAKE, THE FO SAID THAT HE GRIPPED THE CTL TIGHTLY AND PREPARED TO DISCONNECT THE AUTOPLT. THE ACFT SUDDENLY ROLLED TO THE R REACHING 30 DEGS OF BANK EVEN THOUGH THE FO PUT IN FULL L RUDDER AND AILERON. THE ACFT STOPPED THE ROLL AT THAT POINT, HESITATED THEN SLOWLY ROLLED TO A WINGS LEVEL ATTITUDE. HE RELAXED THE CTL INPUTS, HE SAID, BUT A FEW SECONDS LATER THE ACFT ROLLED JUST AS VIOLENTLY TO THE L AGAIN WITH FULL RUDDER AND AILERON TO COUNTER. THIS TIME THE ROLL SEEMED TO STOP AT 20 DEGS THEN VERY SLOWLY INCREASE TOWARD 30 DEGS, BUT DID NOT QUITE MAKE IT THAT FAR. THE ACFT AGAIN HESITATED AT THE MAX BANK ANGLE AND THEN SLOWLY RECOVERED. AFTER THIS IT WAS AGAIN SMOOTH. THE FLC RPTED THE ENCOUNTER TO THE APCH CTLR AND ASKED WHAT KIND OF ACFT IT WAS. THE CTLR, ALLEGEDLY, WOULD ONLY RESPOND THAT THE ACFT WAS 5 MI AHEAD OF THEM AND THEY HAD LEGAL SEPARATION. THE CTLR LATER ASSIGNED THEM A PARALLEL RWY INSTEAD OF REQUIRING THEM TO FOLLOW THE, AS YET UNKNOWN, TFC. AS THE CREW BROKE OUT OF THE CLOUDS ON FINAL APCH THEY COULD SEE THAT THE OTHER ACFT WAS A B767-300. IT WAS NEW AND HAD A LARGE IDENT LOGO ON THE ACFT. THE RPTR SAID THAT HE HAS HAD UNUSUAL ATTITUDE RECOVERY TRAINING AT HIS AIRLINE AND HE FEELS THAT IT WAS VERY HELPFUL DURING THIS ENCOUNTER.

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.