F100 FLT CREW TKOF WITH WARNING HORN SOUNDING.

Narrative

ON THE MORNING OF MAR/SAT/03; CREW TRACKING HAD CHANGED OUR DEP TIME A TOTAL OF 3 TIMES OUT OF YYZ TO ORD. ATTEMPTING TO GET THE FLT OUT SAFELY AND AN ON TIME DEP; MY CAPT AND I REVIEWED THE MEL FOR CORRECT PROCS AND MAINT ACTION. EVERYTHING SEEMED TO COMPLY WITH THE WRITE-UP AND PLACARD FOR THE LIFT DUMPER UNSAFE MESSAGE. DURING THE TKOF WARNING TEST; THE WARNING SOUNDED; AND WE BOTH ASSUMED THIS WAS NORMAL DUE TO THE PLACARDED ITEM. OBVIOUSLY; THE PROC WAS NOT COMPLETELY COMPLIED WITH; AND WE TOOK OFF WITH THE TKOF WARNING SYS SOUNDING AND LIFT DUMPER UNSAFE MESSAGE. AFTER REVIEWING OUR ACTION AND THE ACFT MEL INFLT; WE DETERMINED MAINT SHOULD HAVE PLACARDED MEL ZZZ INSTEAD OF YYY. ACR'S MAINT ALSO SAID WHEN WE LANDED; YYZ MAINT SHOULD ALSO HAVE DISCONNECTED A COUPLE OF CANNON PLUGS. I NOW KNOW THAT WE SHOULD NOT HAVE RECEIVED THE TKOF WARNING SOUND DURING THE TEST; AND DEFINITELY; WE SHOULD NOT HAVE TAKEN OFF WITH THE HORN SOUNDING. I LEARNED A VALUABLE LESSON; AND THIS WILL NOT HAPPEN AGAIN.