ACR X UNAUTH SPD REDUCTION ON FINAL APCH CAUSED ACFT GAR.

Narrative

TFC BACKING UP DURING APCH. RWY 3C CLOSED. WX SOMEWHAT WORSE THAN EXPECTED (CEILING; VISIBILITY AND ICING CONDITIONS). ACR X BEING SLOWED SOMEWHAT BELOW THE USUAL APCH SPDS; AND IN STEPS THAT CAME IN QUICKER SUCCESSION THAN USUAL; AND MOST DSCNTS INCLUDED A REQUEST TO GET THERE QUICKLY. AS WE TURNED ON FINAL; ATC RPTED LIGHT ICE AT 3000 FT. THE ACFT AHEAD OF US WAS 2 1/2 - 3 MI OBSERVED ON TCASII. WE WERE TOLD TO 'CONTINUE' BY LCL. WE ENCOUNTERED MODERATE RIME ICE; AND HAD TO GO TO FLAPS LNDG (40 DEGS) IN ORDER TO HAVE SUFFICIENT BLEED AIR TO ANTI-ICE THE AIRPLANE. THAT CAUSED US TO LOSE 20 KTS; WHICH I WAS TRYING TO RECOVER. THE ACFT BEHIND US WAS AT LEAST 2 1/2 MI (NOT OBSERVED ON TCASII). LCL QUESTIONED OUR SPD; BAWLED US OUT; AND LOST HIS TEMPER. WE DID NOT ARGUE BACK. HE IMMEDIATELY HAD THE AIRPLANE BEHIND MISS THE APCH. WE HAD BEEN ASSIGNED 160 KTS; AND WERE TO HOLD IT TO THE FINAL APCH FIX. AT ABOUT 2 MI OUTSIDE THE FINAL APCH FIX AT ABOUT 3400 FT MSL; WE WENT TO LNDG FLAPS; AND THE AIRSPD BLEED OFF TO 140 KIAS. THE TCASII SHOWED THE ACFT AHEAD TO BE CLOSER THAN THE ONE BEHIND; AND AT ONLY 1 MI OUTSIDE THE FINAL APCH FIX; I DIDN'T THINK THE CHANGE IN OUR SPD WOULD BE SIGNIFICANT. AS WE LANDED; THE ACFT AHEAD WAS JUST CLRING THE HIGH SPD EXIT; AND THE ACFT BEHIND HAD ALREADY MISSED. THE NEXT ACFT LANDED 2 MINS 35 SECONDS LATER. WE RECEIVED OUR LNDG CLRNC JUST PRIOR TO TOUCHDOWN; AND WE WERE ALSO PREPARING TO MISS. MY FEELING IS THAT TFC WAS BUNCHING UP; DUE TO WX WORSE THAN EXPECTED; ICING CONDITIONS; AND A CLOSED RWY. TFC AHEAD WAS BEING VECTORED FOR SPACING AND 2 ACFT HAD TO MISS; AND WE ALMOST DID; TOO. THE CTLRS WERE DOING THE BEST THEY COULD; BUT WERE BECOMING LOADED AND STRESSED.