Narrative:

Long island ground told the copilot and I to taxi to runway 33L from FBO via taxiway south and taxiway east, hold short of runway 33L on taxiway east. We taxied to the hold short line at taxiway east. I misread the hold short signs, and I thought that it was the hold short line for runway 10/28 only. I decided to cross the runway because it was not the active runway and then hold short of runway 33L. Unfortunately, runway 10/28 and runway 33L approach ends touch at that point, and I ended up crossing both runways. I realized my mistake when I saw the '33' numbers on the concrete. My copilot and I were horrified, contacted the tower, and apologized for our dangerous mistake. My first major error was my overconfidence at an airport where I was unfamiliar. I had only flown into this airport once before, and I had not used runway 33L. My second error was not consulting with my copilot who had the airport diagram in front of him. In fact, I should have looked at the airport diagram myself because my copilot is relatively new. Third, I should have verified with the tower if I was supposed to cross runway 10/28. Finally, I should have looked more closely at the runway hold short signs. From now on, I will be much more careful when approaching hold short lines. I have been humbled!

Google
 

Original NASA ASRS Text

Title: BE90 CREW HAD MULTIPLE RWY INCURSIONS AT ISP.

Narrative: LONG ISLAND GND TOLD THE COPLT AND I TO TAXI TO RWY 33L FROM FBO VIA TXWY S AND TXWY E, HOLD SHORT OF RWY 33L ON TXWY E. WE TAXIED TO THE HOLD SHORT LINE AT TXWY E. I MISREAD THE HOLD SHORT SIGNS, AND I THOUGHT THAT IT WAS THE HOLD SHORT LINE FOR RWY 10/28 ONLY. I DECIDED TO CROSS THE RWY BECAUSE IT WAS NOT THE ACTIVE RWY AND THEN HOLD SHORT OF RWY 33L. UNFORTUNATELY, RWY 10/28 AND RWY 33L APCH ENDS TOUCH AT THAT POINT, AND I ENDED UP XING BOTH RWYS. I REALIZED MY MISTAKE WHEN I SAW THE '33' NUMBERS ON THE CONCRETE. MY COPLT AND I WERE HORRIFIED, CONTACTED THE TWR, AND APOLOGIZED FOR OUR DANGEROUS MISTAKE. MY FIRST MAJOR ERROR WAS MY OVERCONFIDENCE AT AN ARPT WHERE I WAS UNFAMILIAR. I HAD ONLY FLOWN INTO THIS ARPT ONCE BEFORE, AND I HAD NOT USED RWY 33L. MY SECOND ERROR WAS NOT CONSULTING WITH MY COPLT WHO HAD THE ARPT DIAGRAM IN FRONT OF HIM. IN FACT, I SHOULD HAVE LOOKED AT THE ARPT DIAGRAM MYSELF BECAUSE MY COPLT IS RELATIVELY NEW. THIRD, I SHOULD HAVE VERIFIED WITH THE TWR IF I WAS SUPPOSED TO CROSS RWY 10/28. FINALLY, I SHOULD HAVE LOOKED MORE CLOSELY AT THE RWY HOLD SHORT SIGNS. FROM NOW ON, I WILL BE MUCH MORE CAREFUL WHEN APCHING HOLD SHORT LINES. I HAVE BEEN HUMBLED!

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.