Narrative:

The problem arose unknowingly after preflight failing to turn transponder on. Then I departed stl en route to VOR navigation back to vbx avoiding ATC at stl in way of TCA. I was transitioning sus airspace and when asked to identify I realized what had been done. I believe I was so used to this situation of flying that day because that was the second time I made the trip that day that I just overlooked it thinking I had turned it on. I think an addition departure checklist would be appropriate so no recurrence could happen.

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Original NASA ASRS Text

Title: PLT OF SMA DEPARTED STL AND FORGOT TO TURN ON TRANSPONDER. TRANSITIONING SAS ATA WAS ASKED TO IDENTIFY. HAD PENETRATED ATA AND PROBABLY STL TCA.

Narrative: THE PROB AROSE UNKNOWINGLY AFTER PREFLT FAILING TO TURN XPONDER ON. THEN I DEPARTED STL ENRTE TO VOR NAV BACK TO VBX AVOIDING ATC AT STL IN WAY OF TCA. I WAS TRANSITIONING SUS AIRSPACE AND WHEN ASKED TO IDENT I REALIZED WHAT HAD BEEN DONE. I BELIEVE I WAS SO USED TO THIS SITUATION OF FLYING THAT DAY BECAUSE THAT WAS THE SECOND TIME I MADE THE TRIP THAT DAY THAT I JUST OVERLOOKED IT THINKING I HAD TURNED IT ON. I THINK AN ADDITION DEP CHKLIST WOULD BE APPROPRIATE SO NO RECURRENCE COULD HAPPEN.

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.