Narrative:

Upon landing at bjc (jefferson county, co) I switched to ground frequency and obtained what I thought was a taxi clearance to the FBO. ATIS had indicated that a crossing runway was closed. I switched momentarily to the FSS frequency to close my flight plan. Upon returning to the ground frequency I was informed that I had crossed a runway without a clearance.

Google
 

Original NASA ASRS Text

Title: C182 PLT LEFT GND CTL FREQ WITHOUT ADVISING THE GND CTLR HE WOULD BE OFF FREQ. HE HAD A RWY INCURSION IN THE PROCESS.

Narrative: UPON LNDG AT BJC (JEFFERSON COUNTY, CO) I SWITCHED TO GND FREQ AND OBTAINED WHAT I THOUGHT WAS A TAXI CLRNC TO THE FBO. ATIS HAD INDICATED THAT A XING RWY WAS CLOSED. I SWITCHED MOMENTARILY TO THE FSS FREQ TO CLOSE MY FLT PLAN. UPON RETURNING TO THE GND FREQ I WAS INFORMED THAT I HAD CROSSED A RWY WITHOUT A CLRNC.

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.