Narrative:

Small aircraft X instructed to land runway 13, hold short of runway 9L for traffic landing and departing runway 9L. Small aircraft X landed runway 13 and stopped on the runway. Medium large transport Y was put in position on runway 9L. I instructed small aircraft X to continue to taxi and turn left on taxiway C. My instrument told me to keep small aircraft X on runway 13 for crossing runway 9L, but to hold him short runway 9L, which I instructed small aircraft X to do. I issued medium large transport Y a departure clearance on runway 9L. I then scanned runway 9R and proceeded with departure instructions for an aircraft to depart runway 9R. Ground control alerted me that small aircraft X had taxied onto runway 9L. As I turned and keyed my microphone to stop small aircraft X, I observed medium large transport Y's wing pass over small aircraft X. It appears that small aircraft X had changed frequency on the runway to ground control because he only acknowledged my initial clearance to land and hold short of runway 9L. After small aircraft X pilots called the tower over the phone, they said they confused txwys C and G. Golf is across runway 9L.

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Original NASA ASRS Text

Title: SMA X FLT CREW TAXIED ONTO AN ACTIVE RWY AFTER BEING TOLD TO HOLD SHORT. A DEPARTING MLG Y CAME CLOSE TO COLLIDING WITH THE SMA X.

Narrative: SMA X INSTRUCTED TO LAND RWY 13, HOLD SHORT OF RWY 9L FOR TFC LNDG AND DEPARTING RWY 9L. SMA X LANDED RWY 13 AND STOPPED ON THE RWY. MLG Y WAS PUT IN POS ON RWY 9L. I INSTRUCTED SMA X TO CONTINUE TO TAXI AND TURN LEFT ON TXWY C. MY INSTR TOLD ME TO KEEP SMA X ON RWY 13 FOR XING RWY 9L, BUT TO HOLD HIM SHORT RWY 9L, WHICH I INSTRUCTED SMA X TO DO. I ISSUED MLG Y A DEP CLRNC ON RWY 9L. I THEN SCANNED RWY 9R AND PROCEEDED WITH DEP INSTRUCTIONS FOR AN ACFT TO DEPART RWY 9R. GND CTL ALERTED ME THAT SMA X HAD TAXIED ONTO RWY 9L. AS I TURNED AND KEYED MY MIC TO STOP SMA X, I OBSERVED MLG Y'S WING PASS OVER SMA X. IT APPEARS THAT SMA X HAD CHANGED FREQ ON THE RWY TO GND CTL BECAUSE HE ONLY ACKNOWLEDGED MY INITIAL CLRNC TO LAND AND HOLD SHORT OF RWY 9L. AFTER SMA X PLTS CALLED THE TWR OVER THE PHONE, THEY SAID THEY CONFUSED TXWYS C AND G. GOLF IS ACROSS RWY 9L.

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.