FLC OF ACR MLG FLIES THROUGH CLRED ALT OF 14000 FT BECAUSE FO THOUGHT THEY WERE CLRED TO 15000 WHEN IN FACT; THE ALT ALERTER HAD SIMPLY BEEN MIS-SET. TCASII ALERTED CREW TO POTENTIAL CONFLICT AT 14500 FT.

Narrative

CLBING OUT OF HSV; WAS CLRED BY ZTL TO CLB TO 14000 FT. OUR READBACK CONFIRMED 14000 FT. AT 14500 FT; ATC QUESTIONED OUR ALT AND AT THE SAME TIME THE TCASII CALLED 'TFC -- TFC.' WE RESPONDED THAT WE WERE CLBING TO 15000 FT; AS SET IN THE ALT ALERT WINDOW. ATC ADVISED THAT WE WERE CLRED TO 14000 FT SO WE IMMEDIATELY DSNDED TO 14000 FT. THE WORKLOAD IMPOSED ON A 2 MAN CREW DURING DEP/ARR ON A SHORT SEGMENT CONTRIBUTED TO THE MISINTERP OF THE ALT ALERT WINDOW. ADDITIONALLY; TURNING AND PULLING THE ALT ALERT KNOB HAS THE POTENTIAL OF MIS-SETTING THE ALT (ESPECIALLY WHEN YOU ARE BUSY). IN THIS INSTANCE; THE ALT WAS SET AT 15000 FT. SUPPLEMENTAL INFO FROM ACN 209976: ZTL CLRED US TO CLB TO WHAT I THOUGHT WAS 15000 FT. I WAS FLYING THE ACFT; WITH THE CAPT HANDLING THE RADIOS. I SAW 15000 FT IN MY FMA. AFTER ESTABLISHING A CLB AT 380 KTS ON THE ARR; I ARMED THE AUTOPLT. THE CAPT TOLD ME TO MONITOR THE CTR WHILE HE ADDRESSED THE PAX. HE TOOK BACK THE RADIOS AS WE WERE PASSING 14500 FT FOR 15000.