THE RPTR IN A JETSTREAM BAE 4100 FOLLOWING A B757 4-5 MI WAS GIVEN AN UNCOMMANDED 45 DEG L ROLL IN SPITE OF FULL R AILERON AND RUDDER APPLICATION BY THE CAPT AND FO. THE BANK SUSTAINED FOR AS LONG AS 5 SECONDS.

Narrative

WHILE ON THE CONVERGING ILS APCH TO RWY 9R INTO PHL; APPROX 4-5 MI (ON TCASII) INTRAIL BEHIND A B757; WE HAVE ENCOUNTERED STRONG WAKE TURB. THE AIRPLANE BEGAN A ROLL TO THE L THAT COULDN'T BE STOPPED BY OPPOSITE AILERON. AT ABOUT 40 DEGS OF BANK; WE BOTH (CAPT AND FO) HAD FULL R RUDDER AND AILERON. FOR ABOUT 5 SECONDS THE BANK ANGLE VARIED BTWN 30 AND 45 DEGS; WHILE THE PITCH WAS OSCILLATING +/-5 DEGS. AFTER CTL WAS REGAINED; WE SLOWED TO INCREASE SEPARATION AND CONTINUED WITH A NORMAL APCH AND LNDG. THE 1 PAX ON BOARD COMPLAINED ABOUT INJURIES FROM THE TURB TO THE AIRLINE REPRESENTATIVE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED HE HAS EXPERIENCED WAKE BEFORE AS HE ROUTINELY GOES INTO JFK AND SUCH ARPTS BEHIND HEAVIES. HE NEVER SUBMITTED A RPT BEFORE ON WAKE. BUT THIS WAS DIFFERENT. HE WAS SCARED; HIS FLT ATTENDANT WAS SCARED AND HIS ONLY PAX WAS SCARED AND INJURED. THE FLT ATTENDANT CLAIMED SHE WAS GOING TO QUIT WHEN SHE GOT BACK TO HOME BASE; BUT SHE DIDN'T. THE RPTR SAID HE NEVER SAW THE B757 VISUALLY BUT ONLY ON HIS TCASII. NOT BEING ON A VISUAL; THE SEPARATION WAS DETERMINED BY THE TFC CTLR. ON FINAL; ABOUT 600 FT ABOVE THE GND; THE CTLR ASKED IF THE RPTR COULD SIDESTEP TO THE ADJACENT RWY. THE CTLR AT THIS TIME DID NOT KNOW ABOUT THE WAKE ENCOUNTER A MIN OR SO PRIOR. THE RPTR GLADLY SIDESTEPPED. THE RPTR STATED THE MOST SIGNIFICANT CONTRIBUTING CAUSE FOR THIS WAKE TURB INCIDENT WAS 4-5 MI SEPARATION UNDER SOME CONDITIONS IS NOT ENOUGH FOR 24000 LB ACFT BEHIND HEAVIES. HE STATED BEING AT THE MERCY OF TFC CTL FOR SPACING THERE IS NOTHING HE WOULD DO DIFFERENTLY BUT NOW HIS VISUAL SEPARATION IS AN EXTRA MI OR SO ON VISUALS WHERE HE ESTABLISHES THE SEPARATION. THE RPTR SUGGESTED ATC INCREASE SEPARATION OF COMMUTER SIZE ACFT BEHIND HEAVIES.