Narrative:

I had filed my IFR flight plan, and before departure from the uncontrolled airport, I called ATC from the ground via radio for my IFR route clearance. The clearance was received and the readback was acknowledged as correct by ATC. No further instructions were received. I then switched to the CTAF frequency to announce my departure intentions, and after a visual traffic check, departed the airport. The WX was VFR with a ceiling of about 3500 ft. Upon climbing through 1200 ft, I contacted new york departure. At this time I was advised that I had departed without being released and told to maintain VFR until I received clearance. Upon receiving this clearance to proceed, the flight was continued normally to my destination without incident. Upon review of procedures, it was apparent to me that I should have indicated to ATC at the time of the fact that I was ready to depart, and then to have specifically requested a clearance release. I attribute my error to the fact that I most often operate out of a controled airport where takeoff clearance by the tower handles IFR release.

Google
 

Original NASA ASRS Text

Title: PA28 PLT TOOK OFF ON AN IFR FLT PLAN WITHOUT GETTING AN IFR RELEASE.

Narrative: I HAD FILED MY IFR FLT PLAN, AND BEFORE DEP FROM THE UNCTLED ARPT, I CALLED ATC FROM THE GND VIA RADIO FOR MY IFR RTE CLRNC. THE CLRNC WAS RECEIVED AND THE READBACK WAS ACKNOWLEDGED AS CORRECT BY ATC. NO FURTHER INSTRUCTIONS WERE RECEIVED. I THEN SWITCHED TO THE CTAF FREQ TO ANNOUNCE MY DEP INTENTIONS, AND AFTER A VISUAL TFC CHK, DEPARTED THE ARPT. THE WX WAS VFR WITH A CEILING OF ABOUT 3500 FT. UPON CLBING THROUGH 1200 FT, I CONTACTED NEW YORK DEP. AT THIS TIME I WAS ADVISED THAT I HAD DEPARTED WITHOUT BEING RELEASED AND TOLD TO MAINTAIN VFR UNTIL I RECEIVED CLRNC. UPON RECEIVING THIS CLRNC TO PROCEED, THE FLT WAS CONTINUED NORMALLY TO MY DEST WITHOUT INCIDENT. UPON REVIEW OF PROCS, IT WAS APPARENT TO ME THAT I SHOULD HAVE INDICATED TO ATC AT THE TIME OF THE FACT THAT I WAS READY TO DEPART, AND THEN TO HAVE SPECIFICALLY REQUESTED A CLRNC RELEASE. I ATTRIBUTE MY ERROR TO THE FACT THAT I MOST OFTEN OPERATE OUT OF A CTLED ARPT WHERE TKOF CLRNC BY THE TWR HANDLES IFR RELEASE.

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.