Narrative:

After passing djb VOR arrival fix, approach control slowed us to 210 KTS and allowed B737 to overtake us (from above). At approximately 12 mi right base turn for runway 23L ILS, our beech had the first encounter of wake from the B737 initial descent through our altitude. It was only slight buffeting. Anticipating further wake turbulence avoidance, the captain flew 1 to 1 1/2 dots high on the GS. The B737 was flying above the GS as evidenced by our TCASII and visually saw the B737 'elevator' down around 2-3 DME. We were 5 mi in trail. At 8 DME we encountered strong wake turbulence, which snapped our beech into a 35+ degree rapid bank to the right accompanied with buffeting. After being caught in the bank for 2-3 seconds, we leveled the aircraft. Our airspeed was 180 KTS, just prior to lowering gear, at the wake encounter. We remained 1 1/2 to 2 dots high on GS for remainder of approach and did not encounter further wake. I believe that the B737 flying the visual well above GS contributed to our second and most severe wake encounter. Cle has a good mix of commuter and airline traffic during bank times. It is proper and considerate for airliners to maintain GS so that commuters, who typically fly 1 to 1 1/2 DOT high to avoid wake, can do so. At our company it is SOP to back up visuals with approach navaids, so even during visuals a GS is referenced. The beech 1900 is capable of maintaining speeds of 220 KTS in the initial approach segment which is compatible with airline jet traffic. Perhaps jet traffic could remain in sequence behind our turboprop. During a recent visit to ZOB, they mentioned to me how they are beginning to realize that the mighty beech can maintain speeds compatible with the airliners and don't necessarily need to put the jets first. Although in our situation the jet was placed in front of us. For me this wake encounter was a good lesson that normal precautions of remaining high on GS and 5 NM in trail may not always be enough to avoid wake. I pay more attention to the preceding jet's visual descent now so that extra precaution can be taken, including slowing to increase separation, if necessary. This encounter also confirmed that, despite light winds and smooth approach, wake turbulence is stronger and worse than typical light LLWS (low level windshear) found on gusty days. Callback conversation with reporter revealed the following information: the reporter felt that the incident occurred because the B737 was placed in front of his aircraft after being behind them, at a higher altitude. 'His descent through our altitude was then an established fact and requirement.' there was no opportunity for the crew to be higher and above the B737's wake. Had he to do over again he would have stayed to the upwind side of the localizer, in this case, the right side. The BE1900 can maintain 220 KTS for the initial approach, ATC should allow this smaller aircraft to precede the heavier aircraft if there is an apparent 'tie' at the approach gate. The crew suffered a mild case of trauma for a short time after this event. One passenger getting off the flight felt that what had occurred wasn't proper and was slightly upset.

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Original NASA ASRS Text

Title: A BE1900 ON APCH AT CLE EXPERIENCES AN ENCOUNTER WITH WAKE TURB 5 MI BEHIND A B737. APCH CTLR HAD PLANNED THE B737 TO OVERTAKE THE BE1900 AND IT HAD TO DSND DOWN THROUGH THE LTT'S ALT ON FINAL TO ILS RWY 23L.

Narrative: AFTER PASSING DJB VOR ARR FIX, APCH CTL SLOWED US TO 210 KTS AND ALLOWED B737 TO OVERTAKE US (FROM ABOVE). AT APPROX 12 MI R BASE TURN FOR RWY 23L ILS, OUR BEECH HAD THE FIRST ENCOUNTER OF WAKE FROM THE B737 INITIAL DSCNT THROUGH OUR ALT. IT WAS ONLY SLIGHT BUFFETING. ANTICIPATING FURTHER WAKE TURB AVOIDANCE, THE CAPT FLEW 1 TO 1 1/2 DOTS HIGH ON THE GS. THE B737 WAS FLYING ABOVE THE GS AS EVIDENCED BY OUR TCASII AND VISUALLY SAW THE B737 'ELEVATOR' DOWN AROUND 2-3 DME. WE WERE 5 MI IN TRAIL. AT 8 DME WE ENCOUNTERED STRONG WAKE TURB, WHICH SNAPPED OUR BEECH INTO A 35+ DEG RAPID BANK TO THE R ACCOMPANIED WITH BUFFETING. AFTER BEING CAUGHT IN THE BANK FOR 2-3 SECONDS, WE LEVELED THE ACFT. OUR AIRSPD WAS 180 KTS, JUST PRIOR TO LOWERING GEAR, AT THE WAKE ENCOUNTER. WE REMAINED 1 1/2 TO 2 DOTS HIGH ON GS FOR REMAINDER OF APCH AND DID NOT ENCOUNTER FURTHER WAKE. I BELIEVE THAT THE B737 FLYING THE VISUAL WELL ABOVE GS CONTRIBUTED TO OUR SECOND AND MOST SEVERE WAKE ENCOUNTER. CLE HAS A GOOD MIX OF COMMUTER AND AIRLINE TFC DURING BANK TIMES. IT IS PROPER AND CONSIDERATE FOR AIRLINERS TO MAINTAIN GS SO THAT COMMUTERS, WHO TYPICALLY FLY 1 TO 1 1/2 DOT HIGH TO AVOID WAKE, CAN DO SO. AT OUR COMPANY IT IS SOP TO BACK UP VISUALS WITH APCH NAVAIDS, SO EVEN DURING VISUALS A GS IS REFED. THE BEECH 1900 IS CAPABLE OF MAINTAINING SPDS OF 220 KTS IN THE INITIAL APCH SEGMENT WHICH IS COMPATIBLE WITH AIRLINE JET TFC. PERHAPS JET TFC COULD REMAIN IN SEQUENCE BEHIND OUR TURBOPROP. DURING A RECENT VISIT TO ZOB, THEY MENTIONED TO ME HOW THEY ARE BEGINNING TO REALIZE THAT THE MIGHTY BEECH CAN MAINTAIN SPDS COMPATIBLE WITH THE AIRLINERS AND DON'T NECESSARILY NEED TO PUT THE JETS FIRST. ALTHOUGH IN OUR SIT THE JET WAS PLACED IN FRONT OF US. FOR ME THIS WAKE ENCOUNTER WAS A GOOD LESSON THAT NORMAL PRECAUTIONS OF REMAINING HIGH ON GS AND 5 NM IN TRAIL MAY NOT ALWAYS BE ENOUGH TO AVOID WAKE. I PAY MORE ATTN TO THE PRECEDING JET'S VISUAL DSCNT NOW SO THAT EXTRA PRECAUTION CAN BE TAKEN, INCLUDING SLOWING TO INCREASE SEPARATION, IF NECESSARY. THIS ENCOUNTER ALSO CONFIRMED THAT, DESPITE LIGHT WINDS AND SMOOTH APCH, WAKE TURB IS STRONGER AND WORSE THAN TYPICAL LIGHT LLWS (LOW LEVEL WINDSHEAR) FOUND ON GUSTY DAYS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FELT THAT THE INCIDENT OCCURRED BECAUSE THE B737 WAS PLACED IN FRONT OF HIS ACFT AFTER BEING BEHIND THEM, AT A HIGHER ALT. 'HIS DSCNT THROUGH OUR ALT WAS THEN AN ESTABLISHED FACT AND REQUIREMENT.' THERE WAS NO OPPORTUNITY FOR THE CREW TO BE HIGHER AND ABOVE THE B737'S WAKE. HAD HE TO DO OVER AGAIN HE WOULD HAVE STAYED TO THE UPWIND SIDE OF THE LOC, IN THIS CASE, THE R SIDE. THE BE1900 CAN MAINTAIN 220 KTS FOR THE INITIAL APCH, ATC SHOULD ALLOW THIS SMALLER ACFT TO PRECEDE THE HEAVIER ACFT IF THERE IS AN APPARENT 'TIE' AT THE APCH GATE. THE CREW SUFFERED A MILD CASE OF TRAUMA FOR A SHORT TIME AFTER THIS EVENT. ONE PAX GETTING OFF THE FLT FELT THAT WHAT HAD OCCURRED WASN'T PROPER AND WAS SLIGHTLY UPSET.

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.