Narrative:

After landing at mdw, we were directed to the runway 22L hold pad to wait for our gate to open. I positioned the aircraft on taxiway right facing east. After approximately 10 mins our gate cleared and we were given directions to taxi. The controller told us to turn left on taxiway north and hold short of 4R. I figured (assumed) that he must have meant 'turn left on taxiway P, hold short of runway 4R.' as I began making my left turn from taxiway north to taxiway P, I realized I had made a mistake. A beech king air had lifted off runway 4L and was approximately 100 ft in the air. Our horizontal distance to aircraft was approximately 1000 ft. As we crossed the hold short line, I heard ground tell us to stop. He then cleared us to hold short of runway 4R at taxiway P. We are almost always given taxiway P as the taxiway to cross runway 4R and I think that when we received our initial clearance, I did what I have done hundreds of times before. There were a number of aircraft pushed back, blocking the ramp/txwys by taxiway north and I mistakenly assumed that the controller wanted us on taxiway P, especially since taxiway P provided a straight in approach to our gate.

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Original NASA ASRS Text

Title: B737-800 CREW HAD A RWY INCURSION AT RWY 4L AT MDW.

Narrative: AFTER LNDG AT MDW, WE WERE DIRECTED TO THE RWY 22L HOLD PAD TO WAIT FOR OUR GATE TO OPEN. I POSITIONED THE ACFT ON TXWY R FACING E. AFTER APPROX 10 MINS OUR GATE CLRED AND WE WERE GIVEN DIRECTIONS TO TAXI. THE CTLR TOLD US TO TURN L ON TXWY N AND HOLD SHORT OF 4R. I FIGURED (ASSUMED) THAT HE MUST HAVE MEANT 'TURN L ON TXWY P, HOLD SHORT OF RWY 4R.' AS I BEGAN MAKING MY L TURN FROM TXWY N TO TXWY P, I REALIZED I HAD MADE A MISTAKE. A BEECH KING AIR HAD LIFTED OFF RWY 4L AND WAS APPROX 100 FT IN THE AIR. OUR HORIZ DISTANCE TO ACFT WAS APPROX 1000 FT. AS WE CROSSED THE HOLD SHORT LINE, I HEARD GND TELL US TO STOP. HE THEN CLRED US TO HOLD SHORT OF RWY 4R AT TXWY P. WE ARE ALMOST ALWAYS GIVEN TXWY P AS THE TXWY TO CROSS RWY 4R AND I THINK THAT WHEN WE RECEIVED OUR INITIAL CLRNC, I DID WHAT I HAVE DONE HUNDREDS OF TIMES BEFORE. THERE WERE A NUMBER OF ACFT PUSHED BACK, BLOCKING THE RAMP/TXWYS BY TXWY N AND I MISTAKENLY ASSUMED THAT THE CTLR WANTED US ON TXWY P, ESPECIALLY SINCE TXWY P PROVIDED A STRAIGHT IN APCH TO OUR GATE.

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.