WAKE TURB ENCOUNTER ON ARR AT DEN.

Narrative

ATC CALLED TFC (B757) 5 MINS PRIOR TO EVENT. WE WERE 4 1/2 MI IN TRAIL OF THE B757. THE B757 DSNDED INTO IMC AND WE LOST SIGHT OF IT. SHORTLY; WE DSNDED INTO IMC. A FEW MINS LATER WE EXPERIENCED A 45 DEG ROLL TO THE R. I HAVE NO IDEA HOW FAR AHEAD THE B757 WAS WHEN WE ROLLED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR PARTICIPATED IN THE WAKE TURB STRUCTURED CALLBACK PROGRAM. RPTR STATED THAT THE SHOCK OF THE WAKE WAS VERY STRONG; ROLLING HIS ACFT 50 DEGS IN BANK. THE DURATION WAS LENGTHY; LASTING OVER 10 SECONDS. THE QUESTION ARISES FROM THE FLC; CAN'T SOMETHING BE DONE TO KEEP FOLLOWING ACFT AWAY FROM THE WAKE OF A LARGER ACFT IN FRONT OF THEM. THIS FLC WAS FLYING IN IMC CONDITIONS AND HAD NO IDEA OF WHERE TO MOVE SO AS TO AVOID THE WAKE. THEY HOPE THERE IS A BETTER WAY TO SEPARATE TFC DURING AN ARR. FLT PATH DISPLACEMENT WAS SMALL; ABOUT 50 FT; BUT WHAT FELT SIGNIFICANT TO THE RPTR WAS THE SHARPNESS AND SEVERITY OF THE ROLL. BOTH PLTS GRABBED FOR THE CTLS. ACFT RESPONDED WELL TO THE CTL INPUTS BUT WAS SUBJECT TO THE WAKE FOR A LONG DURATION.