FLC OF MLG AT 4000 HAD TCASII RA (DSND) FLT HAD BEEN CLRED TO 3000. FLC EXPEDITED DSCNT; CLRED RA.

Narrative

WE HAD ACCOMPLISHED THE BLUE RIDGE ARR AND NOW ON RADAR VECTORS FOR THE ILS 17L (1) AT DFW. OUR SPD WAS 180 KTS ASSIGNED AND ALT 4000 FT; OUR HDG WAS 240 DEG. ATC APCH CTL THEN HAD A SHIFT CHANGE BECAUSE THE VOICE HAD CHANGED. WE WERE THEN TOLD TO TURN L TO A HDG OF 170 DEG AND INTERCEPT THE ILS 17L LOC AND THAT WE WOULD 'OVERFLY THE CENTERLINE AND MAY OBSERVE TFC ON THE APCH TO 18R AT 3000 FT WHO WOULD ALSO BE OVERFLYING THE LOC E OF COURSE UNDER US.' AT THIS POINT IN TIME WE WERE ALMOST SOLID IFR; HOWEVER; WE DID HAVE VISUAL CONTACT WITH THE OTHER ACFT INTERMITTENTLY. THE NEXT CLRNC FROM ATC ADVISED US THAT WE WERE TO SLOW TO 170 KTS AND THEN DSND TO 3000 FT AND CLRED FOR THE ILS RWY 17L. AFTER SLOWING TO 170 KTS AND JUST BEGINNING TO DSND TCASII ISSUED US A RA TO 'DSND; DSND NOW' AND THE VSI SHOWED A DSND COMMAND OF ABOUT 1000 FPM RATE TO CLR THE CONFLICT. WE INTERMITTENTLY SAW THE CONFLICTING TFC; IT WAS A COMMUTER ACFT ON THE DOWNWIND LEG FOR THE SAME ILS THAT WE WERE ON. THE ACFT APPEARED TO BE AN MDT. WE WERE ESTABLISHED ON THE CENTERLINE OF THE ILS 17L WHEN THIS OCCURRED; WE ALSO CONCURRED WITH EACH OTHER IN THE COCKPIT THAT WE WERE IN FACT ON THE RIGHT ILS AND THAT WE WERE DOING AS PER THE ATC INSTRUCTIONS. THE TFC WAS NOT A REAL THREAT TO OUR APCH AND WE DID NOT ALTER OUR COURSE EXCEPT THAT I DID EXPEDITE OUR DSCNT TO 3000 FT AND TCASII ISSUED A 'CLR OF CONFLICT' ALMOST IMMEDIATELY AFTER WE STARTED TO DSND. APPARENTLY ATC APCH CTL WAS VERY BUSY WITH TFC AND A SHIFT CHANGE AND ALLOWED THINGS TO GET OUT OF HAND; ALSO THE WX WAS A FACTOR. WE DID NOT HAVE TO VIOLATE OR DSND TO AVOID THIS TFC AND BECAUSE WE WERE ALREADY CLRED TO 3000 FT ANYWAY WE DID NOT DEV FROM APCH'S INSTRUCTIONS. IT WAS A SURPRISE TO GET A RA IN IFR CONDITIONS AND TO SEE OTHER TFC IN CLOSE PROX WHILE ON AN ILS APCH.