ALTDEV ALT EXCURSION.

Narrative

WE WERE ORIGINALLY SCHEDULED TO DEPART SYR AT AH:35 PM EST. OPERATIONS PHONED THE HOTEL TO INFORM US THE FLT WOULD BE CANCELLED DUE TO A MAINT PROBLEM WITH THE INBOUND EQUIP. WE WERE SET UP TO FERRY THE ACFT AT BA:00 PM EST; AFTER REPAIRS WERE SCHEDULED TO BE COMPLETED. AFTER CONFERRING WITH MAINT WE FURTHER DELAYED OUR ESTIMATED DEP TIME UNTIL BC:15 PM EST. THE FERRY FLT DEPARTED SYR AT 00:AE PM EST. IT WAS THE FO'S LEG. WE LEVELED AT AN INTERMEDIATE CRUISE ALT OF FL330 IN THE VICINITY OF PSB VOR. CTR CALLED AND RPTED 'XING TFC (APPROX) 20 MI AT FL350; EXPECT FL350 CLR TFC.' I ACKNOWLEDGED. THE NEXT MOMENT I SAW THE FO INITIATING A CLB. I IMMEDIATELY SAID 'DSND NOW' AND PUSHED FORWARD ON THE CTL YOLK. THE FO REPLIED 'WE'RE CLRED TO FL350.' I REPEATED 'DSND NOW'; HAD THE AUTOPLT DISCONNECTED AND PUSHED FORWARD ON THE CTLS. THE ACFT CLBED APPROX 500 FT BEFORE RETURNING TO LEVEL FLT AT FL330 A FEW SECONDS LATER. ONCE THE ACFT WAS REESTABLISHED IN LEVEL FLT AND THE AUTOPLT REENGAGED I NOTICED THAT THE FO HAD RESET THE ALT ALERT DEVICE TO 35000 FT. IT WAS RETURNED TO ITS PROPER SETTING. WE DISCUSSED THE ALTDEV AND I FIRMLY BELIEVE THAT THE FO HEARD (THOUGHT HE HEARD) A CLRNC TO FL350. I RE- EMPHASIZED THE IMPORTANCE OF ORALLY READING BACK ALL FLT PATH CHANGES TO THE OTHER CREW MEMBER BEFORE THEY ARE INITIATED. CONTRIBUTING TO THIS SITUATION I BELIEVE WAS FATIGUE FROM A DAY OF LENGTHY DELAYS AND FROM BOREDOM; SITTING AROUND WITH AN UNDETERMINED DELAY. FROM A TECHNICAL POINT OF VIEW WE MAY NOT HAVE BEEN ON DUTY (SITTING IN A HOTEL ROOM; BEING UPDATED HRLY FROM OPS); HOWEVER; WE DEPARTED APPROX 8 HRS AFTER OUR SCHEDULED DEP WELL OFF THE DIURNAL CYCLE WE HAD SET BY ARISING EARLY IN ANTICIPATION OF AN EARLY DEP THE SUBSEQUENT DAY. NO MENTION OF THE ALTDEV WAS MADE BY ATC.