Narrative:

We were cleared to taxi to runway 12L from FBO (located north of the approach end of runway 22). On the terminal apron ground control instructed us to follow an medium large transport which was northbound on taxiway C ahead and to our left. We followed the medium large transport just short of 12L when ground control instructed us to turn right on taxiway east and hold short for a full length departure. The medium large transport continued on taxiway D and into position on 12L and cleared for takeoff by tower. We were still on taxiway D as the PNF finished the taxi checklist. He was not fully aware of our position in relation to 12L and began giving me directions to taxiway east. Neither one of us was sure of which way to proceed, so I halted the aircraft on D prior to 12L. I continued to taxi on D and made a right turn on what I thought to be east. As I made the right turn ground control brought to my attention I was squarely on runway 12L! (I do not remember seeing a runway hold line prior to venturing onto 12L.) ground control advised there was no conflict and to continue across 12L on D and hold short of 12R. As PIC I accept responsibility for my actions. I put too much trust in following the medium large transport even though I was aware of my position until becoming confused as to which way to turn for taxiway east. We used the taxiway diagram but became confused due to the close proximity of 3 runways. The lack of better runway hold lines or signs in such an area--I recommend a type of attention letter.

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Original NASA ASRS Text

Title: CPR LTT TAXIED ONTO ACTIVE RWY THINKING IT WAS A TXWY.

Narrative: WE WERE CLRED TO TAXI TO RWY 12L FROM FBO (LOCATED N OF THE APCH END OF RWY 22). ON THE TERMINAL APRON GND CTL INSTRUCTED US TO FOLLOW AN MLG WHICH WAS NBOUND ON TXWY C AHEAD AND TO OUR LEFT. WE FOLLOWED THE MLG JUST SHORT OF 12L WHEN GND CTL INSTRUCTED US TO TURN RIGHT ON TXWY E AND HOLD SHORT FOR A FULL LENGTH DEP. THE MLG CONTINUED ON TXWY D AND INTO POS ON 12L AND CLRED FOR TKOF BY TWR. WE WERE STILL ON TXWY D AS THE PNF FINISHED THE TAXI CHKLIST. HE WAS NOT FULLY AWARE OF OUR POS IN RELATION TO 12L AND BEGAN GIVING ME DIRECTIONS TO TXWY E. NEITHER ONE OF US WAS SURE OF WHICH WAY TO PROCEED, SO I HALTED THE ACFT ON D PRIOR TO 12L. I CONTINUED TO TAXI ON D AND MADE A RIGHT TURN ON WHAT I THOUGHT TO BE E. AS I MADE THE RIGHT TURN GND CTL BROUGHT TO MY ATTN I WAS SQUARELY ON RWY 12L! (I DO NOT REMEMBER SEEING A RWY HOLD LINE PRIOR TO VENTURING ONTO 12L.) GND CTL ADVISED THERE WAS NO CONFLICT AND TO CONTINUE ACROSS 12L ON D AND HOLD SHORT OF 12R. AS PIC I ACCEPT RESPONSIBILITY FOR MY ACTIONS. I PUT TOO MUCH TRUST IN FOLLOWING THE MLG EVEN THOUGH I WAS AWARE OF MY POS UNTIL BECOMING CONFUSED AS TO WHICH WAY TO TURN FOR TXWY E. WE USED THE TXWY DIAGRAM BUT BECAME CONFUSED DUE TO THE CLOSE PROX OF 3 RWYS. THE LACK OF BETTER RWY HOLD LINES OR SIGNS IN SUCH AN AREA--I RECOMMEND A TYPE OF ATTN LETTER.

Data retrieved from NASA's ASRS site as of August 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.