Narrative:

On initial approach descending through 4700 ft, encountered moderate wake turbulence. We were approximately 7 mi behind traffic. On final approach to landing runway 17R at dfw at approximately 5 mi behind traffic, we encountered a moderate roll to the left at approximately 30 degrees. We inquired approach control as to what type aircraft was in front of us, and they said it was a company 757. We gave them the wake turbulence report and they told us we had a 5 mi separation with the aircraft. Callback conversation with reporter revealed the following information: the reporter stated that there were actually 2 encounters with wake turbulence during this approach with the first being the strongest. He feels that this was the strongest encounter in 15 yrs of flight. The aircraft was on autoplt at the onset of the first encounter and the autoplt disconnected as the roll began to increase. He felt that the aircraft was still ctlable, however. The reporter thinks that the B757 wing creates the strongest wake of the large narrow bodied aircraft and that the controllers are not very concerned. He wants more separation, including if possible, even separate runways.

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Original NASA ASRS Text

Title: WAKE TURB IN THE TFC PATTERN.

Narrative: ON INITIAL APCH DSNDING THROUGH 4700 FT, ENCOUNTERED MODERATE WAKE TURB. WE WERE APPROX 7 MI BEHIND TFC. ON FINAL APCH TO LNDG RWY 17R AT DFW AT APPROX 5 MI BEHIND TFC, WE ENCOUNTERED A MODERATE ROLL TO THE L AT APPROX 30 DEGS. WE INQUIRED APCH CTL AS TO WHAT TYPE ACFT WAS IN FRONT OF US, AND THEY SAID IT WAS A COMPANY 757. WE GAVE THEM THE WAKE TURB RPT AND THEY TOLD US WE HAD A 5 MI SEPARATION WITH THE ACFT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT THERE WERE ACTUALLY 2 ENCOUNTERS WITH WAKE TURB DURING THIS APCH WITH THE FIRST BEING THE STRONGEST. HE FEELS THAT THIS WAS THE STRONGEST ENCOUNTER IN 15 YRS OF FLT. THE ACFT WAS ON AUTOPLT AT THE ONSET OF THE FIRST ENCOUNTER AND THE AUTOPLT DISCONNECTED AS THE ROLL BEGAN TO INCREASE. HE FELT THAT THE ACFT WAS STILL CTLABLE, HOWEVER. THE RPTR THINKS THAT THE B757 WING CREATES THE STRONGEST WAKE OF THE LARGE NARROW BODIED ACFT AND THAT THE CTLRS ARE NOT VERY CONCERNED. HE WANTS MORE SEPARATION, INCLUDING IF POSSIBLE, EVEN SEPARATE RWYS.

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.