Narrative:

Kalamazoo tower was closed, and so was kalamazoo approach control, so we wre talking to ZAU on the ground at kalamazoo to get our IFR clearance. After getting the clearance, we were told to 'hold for release, advise ready for departure.' after that, we switched over to the CTAF frequency to advise of our position while taxiing. There was some confusion on which runway to use (calm wind), and we were both a bit distraction (taxiing at the dark airport). When we were ready for departure, we announced our intentions on the CTAF frequency, and forgot to go back over to tell chicago that we were ready for departure. We departed into VFR WX without being cleared for takeoff on our IFR clearance. We called chicago immediately after takeoff and informed the controller that we were in the air. He told us that we didn't have a departure clearance.

Google
 

Original NASA ASRS Text

Title: A KING AIR 200 FLT CREW DEPARTS AN UNCTLED FIELD, INTENDING TO FLY IFR WITHOUT RECEIVING AN IFR RELEASE FROM ATC.

Narrative: KALAMAZOO TWR WAS CLOSED, AND SO WAS KALAMAZOO APCH CTL, SO WE WRE TALKING TO ZAU ON THE GND AT KALAMAZOO TO GET OUR IFR CLRNC. AFTER GETTING THE CLRNC, WE WERE TOLD TO 'HOLD FOR RELEASE, ADVISE READY FOR DEP.' AFTER THAT, WE SWITCHED OVER TO THE CTAF FREQ TO ADVISE OF OUR POS WHILE TAXIING. THERE WAS SOME CONFUSION ON WHICH RWY TO USE (CALM WIND), AND WE WERE BOTH A BIT DISTR (TAXIING AT THE DARK ARPT). WHEN WE WERE READY FOR DEP, WE ANNOUNCED OUR INTENTIONS ON THE CTAF FREQ, AND FORGOT TO GO BACK OVER TO TELL CHICAGO THAT WE WERE READY FOR DEP. WE DEPARTED INTO VFR WX WITHOUT BEING CLRED FOR TKOF ON OUR IFR CLRNC. WE CALLED CHICAGO IMMEDIATELY AFTER TKOF AND INFORMED THE CTLR THAT WE WERE IN THE AIR. HE TOLD US THAT WE DIDN'T HAVE A DEP CLRNC.

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.