Narrative:

While on the converging ILS approach to runway 9R into phl, approximately 4-5 mi (on TCASII) intrail behind a B757, we have encountered strong wake turbulence. The airplane began a roll to the left that couldn't be stopped by opposite aileron. At about 40 degrees of bank, we both (captain and first officer) had full right rudder and aileron. For about 5 seconds the bank angle varied between 30 and 45 degrees, while the pitch was oscillating +/-5 degrees. After control was regained, we slowed to increase separation and continued with a normal approach and landing. The 1 passenger on board complained about injuries from the turbulence to the airline representative. Callback conversation with reporter revealed the following information: the reporter stated he has experienced wake before as he routinely goes into jfk and such airports behind heavies. He never submitted a report before on wake. But this was different. He was scared, his flight attendant was scared and his only passenger was scared and injured. The flight attendant claimed she was going to quit when she got back to home base, but she didn't. The reporter said he never saw the B757 visually but only on his TCASII. Not being on a visual, the separation was determined by the traffic controller. On final, about 600 ft above the ground, the controller asked if the reporter could sidestep to the adjacent runway. The controller at this time did not know about the wake encounter a min or so prior. The reporter gladly sidestepped. The reporter stated the most significant contributing cause for this wake turbulence incident was 4-5 mi separation under some conditions is not enough for 24000 pound aircraft behind heavies. He stated being at the mercy of traffic control 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 reporter suggested ATC increase separation of commuter size aircraft behind heavies.

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Original NASA ASRS Text

Title: 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.

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.