WAKE TURB ENCOUNTER.

Narrative

FOLLOW APPROX 3 TO 3.5 MI IN TRAIL OF A B727 ON RIVER VISUAL WE ENCOUNTERED SEVERE WAKE TURB WHICH LASTED APPROX 7 TO 10 SEC. THE VORTEX ENCOUNTERED TOOK FULL R AILERON AND APPROX 15 PERCENT R RUDDER TRAVEL TO CORRECT. BOTH OUR MD80 (AT APPROX 110000 LBS) AND THE LEADING B727 WERE ON APCH (VISUAL) TO RWY 13 AT APPROX 3500 FT TO 3200 FT DSNDING WINGS LEVEL ON THE APCH. THE MOST SEVERE TURB I HAVE EXPERIENCED IN 10 PLUS YRS AIRLINE FLYING. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAYS THAT HE HAS HAD MORE WAKE TURB ENCOUNTERS IN THE LAST 6 MONTHS THAN IN THE PAST 2 YRS. HE BELIEVES THAT THIS IS A RESULT OF ATC PROVIDING LESS SEPARATION BTWN ACFT. HIS FLC WAS ESPECIALLY SURPRISED AT THE SEVERITY OF THE WAKE ENCOUNTER BEING CAUSED BY A NARROW BODY ACFT (B727). THIS ENCOUNTER WAS SO SEVERE THAT RPTR SAYS IF THEY HAD NOT IMMEDIATELY USED FULL AILERON AND COORD RUDDER; THEY COULD HAVE EASILY ROLLED INVERTED. RPTR WAS ALSO CONCERNED ABOUT TKOF PROCS; PARTICULARLY AT DFW. THERE; THEY ARE TAKING ACFT OFF VERY CLOSE TOGETHER. ONE ACFT STILL ON TKOF ROLL WHEN NEXT ACFT IS CLRED FOR TKOF. RPTR SAYS IN ONE INSTANCE; THEY WERE ALREADY AT 100 KTS AND OTHER ACFT; PRECEDING; HAD NOT YET LEFT RWY. THIS SETS UP 2 POTENTIALLY DANGEROUS SITS. ONE; IF THE LEAD ACFT SUDDENLY ABORTED AND THE OTHER IS WAKE TURB FROM CLOSE PROX OF LEAD ACFT. RPTR SAYS IT IS PARTICULARLY BAD IN CALM WINDS BELOW 2000 FT.