Narrative:

While cleared for approach (ILS) at bna at 3000 ft, we were about to configure to land. We then encountered moderate to severe wake turbulence that caused the aircraft to roll approximately 60 degrees. We corrected, flew above the GS to a normal landing. After told to contact the tower, we were told that we were 4 mi in trail of B737. Approach control never informed us we were following any aircraft nor did they ever tell us to reduce speed. After informing tower what happened they apologized. I called the tower on the ground to pass along what happened and to notify approach. Approach control should have notified us if we were in trail of aircraft, especially a B737. This would have allowed us to slow or plan to fly above the GS. Callback conversation with reporter revealed the following information: reporter states that TRACON did not notify them that they were in trail. It was not until they switched to tower that they were informed of following the B737. Reporter believes the B737 must have been brought in from a higher altitude and the wake settled into their path as they were about to intercept the GS. Had they been aware they would certainly have remained above GS and slowed their speed. Most of the time controllers are good about notifying of traffic ahead so one can plan.

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Original NASA ASRS Text

Title: FLC OF CE550 ENCOUNTER WAKE TURB JUST AS THEY ARE INTERCEPTING THE GS. AFTER REGAINING CTL, THEY ARE HIT AGAIN BY THE WAKE. AFTER CHANGING TO TWR FREQ THEY ARE INFORMED THAT THEY ARE IN TRAIL OF A B737.

Narrative: WHILE CLRED FOR APCH (ILS) AT BNA AT 3000 FT, WE WERE ABOUT TO CONFIGURE TO LAND. WE THEN ENCOUNTERED MODERATE TO SEVERE WAKE TURB THAT CAUSED THE ACFT TO ROLL APPROX 60 DEGS. WE CORRECTED, FLEW ABOVE THE GS TO A NORMAL LNDG. AFTER TOLD TO CONTACT THE TWR, WE WERE TOLD THAT WE WERE 4 MI IN TRAIL OF B737. APCH CTL NEVER INFORMED US WE WERE FOLLOWING ANY ACFT NOR DID THEY EVER TELL US TO REDUCE SPD. AFTER INFORMING TWR WHAT HAPPENED THEY APOLOGIZED. I CALLED THE TWR ON THE GND TO PASS ALONG WHAT HAPPENED AND TO NOTIFY APCH. APCH CTL SHOULD HAVE NOTIFIED US IF WE WERE IN TRAIL OF ACFT, ESPECIALLY A B737. THIS WOULD HAVE ALLOWED US TO SLOW OR PLAN TO FLY ABOVE THE GS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT TRACON DID NOT NOTIFY THEM THAT THEY WERE IN TRAIL. IT WAS NOT UNTIL THEY SWITCHED TO TWR THAT THEY WERE INFORMED OF FOLLOWING THE B737. RPTR BELIEVES THE B737 MUST HAVE BEEN BROUGHT IN FROM A HIGHER ALT AND THE WAKE SETTLED INTO THEIR PATH AS THEY WERE ABOUT TO INTERCEPT THE GS. HAD THEY BEEN AWARE THEY WOULD CERTAINLY HAVE REMAINED ABOVE GS AND SLOWED THEIR SPD. MOST OF THE TIME CTLRS ARE GOOD ABOUT NOTIFYING OF TFC AHEAD SO ONE CAN PLAN.

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.