Narrative:

I (aircraft X) received the current ATIS and IFR clearance. I requested and received taxi instruction to runway 5R at tys and proceeded accordingly. Approaching the takeoff point for runway 5R, I called the tower and advised I was ready for takeoff. Tower acknowledged and cleared me into position and hold. I proceeded onto the runway, applied takeoff power and, in fact, took off without a clearance. Retracting the gear, I saw a single engine aircraft (aircraft Y) crossing in front of me (some 2000 ft away by my guess) and my first thought was that he had failed to hold short of runway 5R. My immediate second thought was that I was the one in error -- and of course, the second thought was correct. Communications between the tower and me were clear and correct. I simply allowed myself to be distraction by other radio communications and what I heard and what I wanted to hear were not the same. Takeoff, and climb out continued normally. I feel certain a copilot would have prevented this event (mine is a single pilot operation). Lacking that, complete attention to the task at hand would and will prevent such events.

Google
 

Original NASA ASRS Text

Title: TYS CLRS BE90 INTO POS AND HOLD FOR TFC DEPARTING OFF OTHER RWY, BUT BE90 INITIATES TKOF, CONFLICTING WITH OTHER DEPARTING TFC.

Narrative: I (ACFT X) RECEIVED THE CURRENT ATIS AND IFR CLRNC. I REQUESTED AND RECEIVED TAXI INSTRUCTION TO RWY 5R AT TYS AND PROCEEDED ACCORDINGLY. APCHING THE TKOF POINT FOR RWY 5R, I CALLED THE TWR AND ADVISED I WAS READY FOR TKOF. TWR ACKNOWLEDGED AND CLRED ME INTO POS AND HOLD. I PROCEEDED ONTO THE RWY, APPLIED TKOF PWR AND, IN FACT, TOOK OFF WITHOUT A CLRNC. RETRACTING THE GEAR, I SAW A SINGLE ENG ACFT (ACFT Y) XING IN FRONT OF ME (SOME 2000 FT AWAY BY MY GUESS) AND MY FIRST THOUGHT WAS THAT HE HAD FAILED TO HOLD SHORT OF RWY 5R. MY IMMEDIATE SECOND THOUGHT WAS THAT I WAS THE ONE IN ERROR -- AND OF COURSE, THE SECOND THOUGHT WAS CORRECT. COMS BTWN THE TWR AND ME WERE CLR AND CORRECT. I SIMPLY ALLOWED MYSELF TO BE DISTR BY OTHER RADIO COMS AND WHAT I HEARD AND WHAT I WANTED TO HEAR WERE NOT THE SAME. TKOF, AND CLBOUT CONTINUED NORMALLY. I FEEL CERTAIN A COPLT WOULD HAVE PREVENTED THIS EVENT (MINE IS A SINGLE PLT OP). LACKING THAT, COMPLETE ATTN TO THE TASK AT HAND WOULD AND WILL PREVENT SUCH EVENTS.

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.