FLC ALT BUST. WX AHEAD; CREW WORKLOAD AND VERY HIGH ACFT PERFORMANCE ALL CONTRIBUTING TO BUST.

Narrative

CRUISING AT FL280 (HAD REQUESTED FL310 BUT ATC UNABLE BECAUSE OF TFC). APCHING WX; REQUESTED FL350. TOLD TO EXPECT FL350. FEW MINS LATER I THOUGHT THE CLRNC ISSUED TO US WAS TO CLB TO FL350. I SET FL350 IN ALT SELECTOR AND ANNOUNCED 'FL350 SET AND ARMED.' THE FO WAS AT THE TIME COMPLETING THE RADIO XMISSION. AS I CLBED THROUGH FL290; FO STATED OUR CLRNC WAS ONLY TO FL290. I IMMEDIATELY ARRESTED THE CLB (WE WERE THROUGH APPROX FL298 AT THIS TIME) AND RETURNED TO FL290. APPARENTLY I HAD MISSED THE CTLR XMISSION WHICH I THOUGHT INITIALLY CLRED US TO FL350 AND THEN CHANGED TO FL290 EVIDENTLY BECAUSE OF TFC IN THE AREA. AS WE APCHED FL300 CTLR CALLED US AND STATED OUR CLRNC WAS TO FL290. THE FO HAD UNDERSTOOD THE CLRNC TO FL290 BUT DID NOT HEAR ME STATE 'FL350 SET AND ARMED' BECAUSE HE WAS TALKING ON THE RADIO AT THE TIME. SINCE IT WAS SUCH A SHORT TIME FROM FL280 TO FL290; HE HAD NOT NOTICED FL350 SET IN ALT ALERT WINDOW. I'M NOT SURE HOW THIS INCURSION COULD HAVE BEEN AVOIDED. I FOLLOWED COMPANY PROCS WITH RESPECT TO SETTING A NEW ALT AND STATING THE ALT SET AND ARMED. WE HAD CLBED THROUGH THE CTLR CLRED ALT (FL290) BEFORE FO HAD COMPLETED FREQ CHANGE AND CHKED ALT I HAD SET IN ALT REMINDER WINDOW.