A B757-200 ACFT ENCOUNTERS WAKE TURB AS THE FLC FLARES THE ACFT FOR LNDG AT MSP. FLC EXECUTES GAR.

Narrative

SIMULTANEOUS ILS APCHS WERE BEING CONDUCTED TO RWYS 29L AND 29R WITH A RPTED WIND OF 180 DEGS AT 5 KTS. DURING THE LNDG FLARE ON RWY 29R WE EXPERIENCED A ROLLING MOMENT TO THE L AND THEN TO THE R. AN IMMEDIATE GAR WAS EXECUTED AND THE NEXT APCH AND LNDG WAS UNEVENTFUL. AFTER DISCUSSING THE INCIDENT WITH THE FO WE SUSPECTED THIS WAS CAUSED BY THE WAKE TURB FROM HVY ACFT MAKING APCHS TO RWY 29L. WITH A LIGHT WIND FROM THE S THIS WOULD EXPLAIN HOW THE WINGTIP VORTICES FROM ACFT LNDG ON RWY 29L COULD DRIFT OVER TO THE TOUCHDOWN ZONE OF RWY 29R. IT IS A COMMON PRACTICE IN MSP FOR THE HVY ACFT TO LAND ON RWY 29L BECAUSE IT IS ONE OF THE LONGEST RWYS AND IT IS CLOSE TO THE INTL GATES. AN ADVISORY OF THIS POTENTIAL FLT HAZARD SHOULD BE ISSUED ON THE ATIS FREQ OR BY APCH CTL PRIOR TO COMMENCING THE APCH WITH APPROPRIATE SEPARATION BTWN HVY ACFT ON RWY 29L AND ACFT COMMENCING APCHS TO RWY 29R. AN ADVISORY WAS XMITTED TO GND CTL AFTER WE PARKED AT THE GATE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR PARTICIPATED IN THE WAKE TURB STRUCTURED CALLBACK PROGRAM. THE RPTR'S ACFT WAS ROCKED QUICKLY BACK AND FORTH IN 15 DEG BANKS CLOSE TO THE GND. BECAUSE OF THE CLOSE PROX TO THE GND; THE CAPT QUICKLY MADE THE DECISION TO EXECUTE A GAR. IT WAS NEVER DETERMINED WHAT KIND OF ACFT CREATED THE WAKE; AS ALL ACFT LNDG ON THE L RWY HAD PREVIOUSLY LANDED SOME TIME BEFORE THE B757 FLARE.