Narrative:

Level at 5000 ft, talking to departure. They asked us to change our transponder code. Thought nothing about that request. Later, the first officer decided to pull up to ACARS message to check to see if he set it wrong. Then he realized he had put the wrong trip number in the ACARS which was caught during pushback. He then thought we may have used someone else's clearance. But looking back in the message file in the ACARS he couldn't find any pre departure clearance message. I concluded from all that information is that we took off without an ATC clearance. How ground control let us taxi is beyond me.

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Original NASA ASRS Text

Title: AN ACR MLG CREW TOOK OFF WITHOUT AIRWAYS CLRNC. PDC PROCS WERE IN USE.

Narrative: LEVEL AT 5000 FT, TALKING TO DEP. THEY ASKED US TO CHANGE OUR XPONDER CODE. THOUGHT NOTHING ABOUT THAT REQUEST. LATER, THE FO DECIDED TO PULL UP TO ACARS MESSAGE TO CHK TO SEE IF HE SET IT WRONG. THEN HE REALIZED HE HAD PUT THE WRONG TRIP NUMBER IN THE ACARS WHICH WAS CAUGHT DURING PUSHBACK. HE THEN THOUGHT WE MAY HAVE USED SOMEONE ELSE'S CLRNC. BUT LOOKING BACK IN THE MESSAGE FILE IN THE ACARS HE COULDN'T FIND ANY PDC MESSAGE. I CONCLUDED FROM ALL THAT INFO IS THAT WE TOOK OFF WITHOUT AN ATC CLRNC. HOW GND CTL LET US TAXI IS BEYOND ME.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.