Narrative:

I was located at an FBO at tpa. I copied current ATIS and switched to clearance and obtained my IFR clearance. Upon completion of copying my clearance I contacted ground control on 121.7 and received a clearance to taxi to runway 18L for departure. As I started out I believe ground asked me if an intersection departure would be acceptable. I thought it was an intersection from the active departure runway of runway 18L so I continued my taxi towards runway 18L. I did not recall ground changing my departure to an intersection departure for runway 9. So I continued my taxi to runway 18L believing I was cleared to runway 18L and not told to hold short of runway 9 I proceeded to cross runway 9 en route to runway 18L. It was at this time that ground had me stop my progress in the middle of runway 9 and to immediately contact tower on 119.5 for my departure clearance. In the confusion I advised ground that I believed I was still en route to runway 18L; but would hold present position and contact tower. Tower immediately cleared me for an intersection departure off runway 9. I believe the problem arose due to miscom between pilot and ground control. I was originally cleared to taxi runway 18L with no hold short instructions and when he gave me the intersection departure I failed to realize it was an intersection departure off runway 9; not runway 18L which I had written down on my note pad. I believe that I should have doublechked my taxi instructions since I was unfamiliar with the airport and as I was taxiing to runway 18L I had questioned myself; but did not query ATC on the departure intersection.

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Original NASA ASRS Text

Title: PA32 PLT HAS A RWY INCURSION AT TPA.

Narrative: I WAS LOCATED AT AN FBO AT TPA. I COPIED CURRENT ATIS AND SWITCHED TO CLRNC AND OBTAINED MY IFR CLRNC. UPON COMPLETION OF COPYING MY CLRNC I CONTACTED GND CTL ON 121.7 AND RECEIVED A CLRNC TO TAXI TO RWY 18L FOR DEP. AS I STARTED OUT I BELIEVE GND ASKED ME IF AN INTXN DEP WOULD BE ACCEPTABLE. I THOUGHT IT WAS AN INTXN FROM THE ACTIVE DEP RWY OF RWY 18L SO I CONTINUED MY TAXI TOWARDS RWY 18L. I DID NOT RECALL GND CHANGING MY DEP TO AN INTXN DEP FOR RWY 9. SO I CONTINUED MY TAXI TO RWY 18L BELIEVING I WAS CLRED TO RWY 18L AND NOT TOLD TO HOLD SHORT OF RWY 9 I PROCEEDED TO CROSS RWY 9 ENRTE TO RWY 18L. IT WAS AT THIS TIME THAT GND HAD ME STOP MY PROGRESS IN THE MIDDLE OF RWY 9 AND TO IMMEDIATELY CONTACT TWR ON 119.5 FOR MY DEP CLRNC. IN THE CONFUSION I ADVISED GND THAT I BELIEVED I WAS STILL ENRTE TO RWY 18L; BUT WOULD HOLD PRESENT POS AND CONTACT TWR. TWR IMMEDIATELY CLRED ME FOR AN INTXN DEP OFF RWY 9. I BELIEVE THE PROB AROSE DUE TO MISCOM BTWN PLT AND GND CTL. I WAS ORIGINALLY CLRED TO TAXI RWY 18L WITH NO HOLD SHORT INSTRUCTIONS AND WHEN HE GAVE ME THE INTXN DEP I FAILED TO REALIZE IT WAS AN INTXN DEP OFF RWY 9; NOT RWY 18L WHICH I HAD WRITTEN DOWN ON MY NOTE PAD. I BELIEVE THAT I SHOULD HAVE DOUBLECHKED MY TAXI INSTRUCTIONS SINCE I WAS UNFAMILIAR WITH THE ARPT AND AS I WAS TAXIING TO RWY 18L I HAD QUESTIONED MYSELF; BUT DID NOT QUERY ATC ON THE DEP INTXN.

Data retrieved from NASA's ASRS site as of January 2009 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.