A B737-200 FOLLOWING A B757-200 ENCOUNTERS WAKE TURB WHILE DSNDING INTO MCO; FL.

Narrative

SMOOTH FLT FROM ISLIP; NY; TO ORLANDO; FL; ON FEB/XX/98. APCH CTL VECTORED US TO LOC RWY 17 (MCO) TO FOLLOW A COMPANY B757 ON A VISUAL APCH. DUE TO HAZY CONDITIONS WE ADVISED THAT WE HAD THE RWY ENVIRONMENT FOR RWY 17 MCO; BUT DID NOT SEE THE B757 PRECEDING US CLRLY ENOUGH TO MAINTAIN WAKE SEPARATION. APCH CLRED US ON A VISUAL APCH; BUT DID NOT TELL US TO FOLLOW THE B757 VISUALLY. I NOTED ON TCASII THAT OUR SEPARATION WAS 4 1/2 MI FROM THE B757. APCH HAD DIRECTED US TO MAINTAIN 170 KIAS UNTIL GLOSI INTXN. I WAS SLOWING TO 165 KIAS TO PROVIDE 5 MI SEPARATION WHEN WE HIT A SHORT CYCLE (1-2 SECONDS) MODERATE TO ALMOST SEVERE WAKE TURB. IT FELT LIKE A HARD LNDG. THERE WAS AN ALMOST SIMULTANEOUS UPWASH AND DOWNWASH; WITH LITTLE SUSTAINED POSITIVE OR NEGATIVE ACCELERATIONS EITHER LATERALLY OR HORIZLY. I REDUCED SPD FURTHER TO APCH REF SPD AND FLEW ABOVE GS TO A NORMAL LNDG. ACFT AND PAX WERE NOT HURT OR DAMAGED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR PARTICIPATED IN THE STRUCTURED CALLBACK PROGRAM. RPTR WAS SURPRISED TO ENCOUNTER ANY WAKE AS THE DSNDING ACFT IN FRONT OF HIS WAS IN SIGHT; XING HIS FLT PATH; AND WAS IN A STEEP DSCNT. BECAUSE HE WAS IN A STEEP DSCNT HIS WAKE WAS STRONGER BECAUSE FULL FLAPS HAD TO BE USED FOR SUCH A STEEP APCH. TURB WAS SHORT LIVED; BUT FELT LIKE A HARD LNDG. NO DAMAGE OR PAX COMPLAINTS. NEXT TIME THE RPTR WOULD TAKE A DELAY VECTOR OR SLOW DOWN IF HE THOUGHT THE B757 WERE TO BE A THREAT WITH WAKE TURB.