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?