A CANADAIR CL601-3R JET ENCOUNTERS WAKE TURB FROM A DC8 WHILE LNDG AT PHL. FLC ANTICIPATES THE WAKE; AT FIRST SIGNS OF TURB THEY EXECUTE A GAR. FLC HAS HAD MANY OTHER WAKE TURB EVENTS AND HAS GREAT RESPECT FOR ANY SIGNS OF WAKE THAT MIGHT INDICATE A LOSS OF CTL IS ABOUT TO HAPPEN.

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LATE NIGHT TO EARLY MORNING ARR AT PHL. ACFT LNDG TO THE W UTILIZING RWYS 27L AND 27R. WX: RELATIVELY HIGH CEILINGS WITH WINDS AT THE INITIAL APCH ALT AND AT THE SURFACE COMING FROM THE S AT 8-10 KTS OR GREATER; VISIBILITY GOOD. PROB AT HAND: RWYS 27L AND 27R ARE PARALLEL WITH APPROX 1400 FT BTWN RWY CTRLINES; HOWEVER; THEIR RESPECTIVE THRESHOLDS ARE STAGGERED WITH RWY 27L THRESHOLD BEING APPROX 5000 FT FURTHER W THAN THAT OF RWY 27R. PHL ATC LIKES TO ACCOMMODATE ACR CARGO ACFT BY ISSUING APCH CLRNCS TO RWY 27L. (THE ACR RAMP AND TERMINAL ARE JUST ON THE S SIDE OF RWY 27L.) SINCE THE RWYS ARE STAGGERED; THE GLIDE ANGLE FOR RWY 27L IS HIGHER THAN THE ONE FOR RWY 27R IN A GIVEN BLOCK OF AIRSPACE. ATC THEN SEQUENCES OUR ARR FOR RWY 27R BEHIND THE ACR 'HVY' ON APCH FOR RWY 27L. WHILE TRYING TO INTERCEPT OUR RESPECTIVE 'GS'S;' IT BECOMES QUITE OBVIOUS THAT EVEN WITH 4-6 MI IN TRAIL; OUR ALT IS STILL MUCH LOWER THAN THE PRECEDING 'HVY' TO WHERE IT BECOMES NECESSARY TO ADJUST OUR GLIDE PATH TO A MUCH HIGHER THAN NORMAL TRACK. THE SOUTHERLY WIND EXACERBATES THE PROB BY BLOWING THE 'HVY'S' VORTICES RIGHT ONTO OUR FLT PATH MAKING IT VIRTUALLY IMPOSSIBLE FOR US TO DSND TO THE NORMAL GLIDE PATH ZONE IN ORDER TO MAKE A NORMAL LNDG. BOTH OCCURRENCES RESULTED IN A WAKE TURB ENCOUNTER REQUIRING A GAR. ANOTHER DISTRESSING PROB AND ONE THAT NEEDS TO BE ADDRESSED IMMEDIATELY IS THE CAVALIER ATTITUDE OF SOME CTLRS IN REGARD TO THE DEFINITION OF 'HVY' ACFT AND THEIR MENTAL CRITERIA FOR WHICH ACFT PRODUCE MORE OF A WAKE THAN OTHERS. LET IT BE KNOWN THAT A B737 AND A B727 WILL FLIP YOU JUST AS FAST AND HARD AS A B747; B757; B767; AND A B777. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR PARTICIPATED IN THE WAKE TURB STRUCTURED CALLBACK PROGRAM. RPTR'S MAIN COMPLAINT IS THAT HEAVIER ACFT ARE GIVEN HIGHER ALTS TO DSND FROM WHEN APCHING A TERMINAL AND WHEN IN THE TERMINAL AREA THEY ARE GIVEN THE RWY THAT HAS A DISPLACED THRESHOLD. IN BOTH CASES IT PUTS HIS LIGHTER WT ACFT IN A MORE LIKELY PLACE TO ENCOUNTER WAKE TURB. HE REALIZES THERE ARE OTHER REASONS WHY ACFT ARE SEQUENCED THIS WAY; HOWEVER; HE IS VERY WORN OUT FROM ALL THE WAKE ENCOUNTERS HE IS INVOLVED IN AS HE APCHS HIS DEST. HE HAS ENCOUNTERED IT SO MUCH HE CAN PRETTY WELL PREDICT WHEN IT IS GOING TO BE A PROB FOR HIM. HE FIGURES IF HE CAN PREDICT WHEN WAKE IS GOING TO BE A PROB FOR HIM; WHY CAN'T THE CTLRS.