Narrative:

I was the PF as the captain. Upon landing on runway 24R at lax with the WX clear on rollout; the tower controller made 1 call for company number to clear at taxiway aa and hold short of the runway 24L. The first officer failed to acknowledge the radio call and I directed him to respond to the call. Before he could respond; tower called us again; and this time I thought the tower told us to expedite off the runway to cross runway 24L on taxiway aa. I was turning off of runway 24R onto taxiway aa and the first officer went over to operations frequency. I didn't confirm this with first officer even though; in hindsight; he repeated what the controller told him. For some reason; for those few seconds I was under the impression we were to expedite the crossing of runway 24L at taxiway zz. I proceeded to move along taxiway aa toward runway 24L. For some reason I thought there was confusion on the clearance as I approached runway 24L but was comfortable that I was cleared to cross. I looked back toward runway 24L to cross and saw an aircraft on short final. I asked the first officer to confirm we were cleared to cross and he said he thought we were to hold short and called tower to confirm. Tower confirmed we were to hold short. By this time I had rolled a few ft past the hold short line but 10-20 ft of entering the runway environment. I told the first officer to call tower and tell them we had crossed the hold short line on taxiway aa. Tower acknowledged the call; directed the aircraft on short final to go around; and after several mins cleared us to cross runway 24L. We were given the phone number to tower and asked to call. I called the tower supervisor shortly after pulling in to the gate. I should have verbally confirmed the directions from tower in a more consistent manner with the first officer. I should not have allowed the first officer to be off the frequency at a critical time and I should not have taxied over the hold short line until I was 100% certain I was cleared to.

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Original NASA ASRS Text

Title: B737 EXITED THE OUTER OF PARALLEL RWYS AND WAS INSTRUCTED TO HOLD SHORT OF THE PARALLEL RWY. SUBSEQUENT INSTRUCTIONS FROM TWR WERE MISINTERPRETED AND THE PF CROSSED THE 'HOLD SHORT' LINE BEFORE COMING TO A STOP.

Narrative: I WAS THE PF AS THE CAPT. UPON LNDG ON RWY 24R AT LAX WITH THE WX CLR ON ROLLOUT; THE TWR CTLR MADE 1 CALL FOR COMPANY NUMBER TO CLR AT TXWY AA AND HOLD SHORT OF THE RWY 24L. THE FO FAILED TO ACKNOWLEDGE THE RADIO CALL AND I DIRECTED HIM TO RESPOND TO THE CALL. BEFORE HE COULD RESPOND; TWR CALLED US AGAIN; AND THIS TIME I THOUGHT THE TWR TOLD US TO EXPEDITE OFF THE RWY TO CROSS RWY 24L ON TXWY AA. I WAS TURNING OFF OF RWY 24R ONTO TXWY AA AND THE FO WENT OVER TO OPS FREQ. I DIDN'T CONFIRM THIS WITH FO EVEN THOUGH; IN HINDSIGHT; HE REPEATED WHAT THE CTLR TOLD HIM. FOR SOME REASON; FOR THOSE FEW SECONDS I WAS UNDER THE IMPRESSION WE WERE TO EXPEDITE THE XING OF RWY 24L AT TXWY ZZ. I PROCEEDED TO MOVE ALONG TXWY AA TOWARD RWY 24L. FOR SOME REASON I THOUGHT THERE WAS CONFUSION ON THE CLRNC AS I APCHED RWY 24L BUT WAS COMFORTABLE THAT I WAS CLRED TO CROSS. I LOOKED BACK TOWARD RWY 24L TO CROSS AND SAW AN ACFT ON SHORT FINAL. I ASKED THE FO TO CONFIRM WE WERE CLRED TO CROSS AND HE SAID HE THOUGHT WE WERE TO HOLD SHORT AND CALLED TWR TO CONFIRM. TWR CONFIRMED WE WERE TO HOLD SHORT. BY THIS TIME I HAD ROLLED A FEW FT PAST THE HOLD SHORT LINE BUT 10-20 FT OF ENTERING THE RWY ENVIRONMENT. I TOLD THE FO TO CALL TWR AND TELL THEM WE HAD CROSSED THE HOLD SHORT LINE ON TXWY AA. TWR ACKNOWLEDGED THE CALL; DIRECTED THE ACFT ON SHORT FINAL TO GO AROUND; AND AFTER SEVERAL MINS CLRED US TO CROSS RWY 24L. WE WERE GIVEN THE PHONE NUMBER TO TWR AND ASKED TO CALL. I CALLED THE TWR SUPVR SHORTLY AFTER PULLING IN TO THE GATE. I SHOULD HAVE VERBALLY CONFIRMED THE DIRECTIONS FROM TWR IN A MORE CONSISTENT MANNER WITH THE FO. I SHOULD NOT HAVE ALLOWED THE FO TO BE OFF THE FREQ AT A CRITICAL TIME AND I SHOULD NOT HAVE TAXIED OVER THE HOLD SHORT LINE UNTIL I WAS 100% CERTAIN I WAS CLRED TO.

Data retrieved from NASA's ASRS site as of January 2009 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.