BA41 CREW HAD ALT OVERSHOOT.

Narrative

I HEARD CTLR SAY 'DSND 12000 FT; THEN QBALL 8000 FT.' IT WAS MY LEG AND WE SHOULD HAVE DISCUSSED THE CLRNC TO BE SURE WE UNDERSTOOD IT. AT 11200 FT; CTLR CALLED AND SAID WE WERE SUPPOSED TO STOP AT 12000 FT. HE SAID HIS CLRNC FOR US WAS 'DSND TO 12000 FT; EXPECT QBALL AT 8000 FT.' I HEARD 'DSND TO 12000 FT; QBALL AT 8000 FT.' AT 11200 FT WHEN THE CTLR CALLED US; WE ASKED IF HE WANTED US TO GO BACK UP TO 12000 FT. HE SAID NO; KEEP COMING DOWN TO 8000 FT.' I BELIEVE 2 THINGS LED TO MY ERROR. 1) WE SHOULD HAVE DISCUSSED THE CLRNC TO BE POSITIVE; AND 2) ON THE QBALL ARR INTO ST LOUIS; 99% OF THE TIME THE CLRNC IS 'DOWN TO 10000 FT; QBALL AT 8000 FT; OR DOWN TO 12000 FT; QBALL AT 8000 FT.' THE CTLR SAID 'DOWN TO 12000 FT; EXPECT QBALL AT 8000 FT.' HE SHOULD HAVE LEFT THE 'EXPECT QBALL AT 8000 FT' PART OUT OF THE CLRNC; IT IS TOO SIMILAR TO THE USUAL CLRNC. THEY KNOW WHAT THE USUAL CLRNC IS AND SHOULD NOT USE SIMILAR TERMS BUT AGAIN IF WE WOULD HAVE DISCUSSED IT MORE I MAY HAVE NOT MADE THIS MISTAKE.