FLT CREW OF B757 MISINTERP ALT CLRNC FROM PBI APCH CTLR AND DSND BELOW PROCEDURAL ALT AT FAF ON ILS IAP TO RWY 9L AT PBI.

Narrative

ON APCH INTO RWY 9L AT WEST PALM BEACH ILS IN THE WX WE WERE CLRED DOWN TO 2000 FT. ON A 180 DEG HDG; AT 2000 FT ON HDG WE WERE CLRED TO 'APPROX 120 DEG HDG INTERCEPT LOC.' THE CTLR THEN CLRED US TO WHAT SOUNDED LIKE 'ONE TWO THOUSAND; CLRED FOR THE APCH.' I READ THAT BACK AND WE PUT IN 1200 FT FOR THE ALT. WE DSNDED AND INTERCEPTED THE LOC (ABOUT 4 MI FROM FAF/RUBIN). AT THE FAF WE REALIZED WE WERE LOW AND THAT WE MISUNDERSTOOD THE CTLR; BUT BY THAT TIME WE HAD THE FIELD IN SIGHT AND HAD AN UNEVENTFUL APCH AND LNDG. THIS MISTAKE STARTED OUT AT OUR DEP ARPT WHEN WE SHOWED UP AT OUR ACFT. AFTER PREFLTING THE AIRPLANE WE WERE SHUFFLED OUT OF IT TO ANOTHER ACFT (EQUIP CHANGE) AND HAD TO QUICKLY DO ANOTHER PREFLT. THIS NEW AIRPLANE HAD 2 FLAPS LOCKED OUT AND NO APU; SO NOT ONLY WERE WE LATE; BUT WE HAD A MAINT CARRYOVER TO DEAL WITH AND HAD TO START AT THE GATE. ALTHOUGH THIS PUT US OUT LATE; WE DID OUR JOBS PROFESSIONALLY AND SAFELY. ONCE WE TOOK OFF AND WERE ENRTE; WE HAD A NORMAL FLT UP TILL WE WERE TURNED OVER TO APCH CTL. APCH CTL WANTED US TO TELL THEM WHEN WE WERE SLOWING DOWN SO THEY COULD FIT US IN BTWN ACFT FOR THE ILS RWY 9L APCH INTO PBI. WE HAD PLANNED ON CONFIGURING EARLY DUE TO THE SPOILERS NOT WORKING 100% AND NOT ALLOWING US TO SLOW AS QUICKLY AS NORMAL. BTWN THE HVY TFC ON THE RADIO; AND SEVERAL TIMES 2 RADIOS BROADCASTING WITH LOUD HIGH SQUEAL AT THE SAME TIME; THERE WAS A MISCOM FROM THE CTLR. READBACK BY ME OF 'ONE TWO THOUSAND' AND; WITH THE CONFIGURING OF THE ACFT AT THE SAME TIME; NEITHER OF US CAUGHT THAT I HAD PUT IN 1200 INTO THE ALT WINDOW. NEITHER THE FO NOR I CAN THINK OF WHAT THE 'ONE TWO THOUSAND' WAS SUPPOSED TO BE. HVY RADIO TFC AND TFC AT THE ARR ARPT ON APCH CTL; AND MISCOM BTWN THE CTLR AND PLTS WERE THE MAJOR PROBS. THE SECONDARY PROB WAS THE MECHANICAL PROB WE HAD TO DEAL WITH THAT WASN'T OUR NORMAL WORKING ENVIRONMENT. THIRDLY; THE LATE SWAPPING OF EQUIP; NIGHTTIME AND WX WERE ADDITIONAL FACTORS THAT LED UP TO OUR PROBS. BETTER COM; LESS TFC ON APCH IN WX AND LESS RADIO TFC WOULD HAVE PROBABLY ALLEVIATED OUR PROBS.