Narrative:

Two parallel runways were in use, the smaller left runway by light aircraft and the larger right by air carriers. We landed on the right with the captain flying. We cleared the right on taxiway O and were told to contact ground. I called ground and was instructed to 'taxi to your gate via charlie (which crosses the left runway at a 45 degree angle at mid-runway) hold short of the left'. We completed the after landing checklist and the captain began to taxi. I advised the captain that I was going to make the passenger announcement and asked if he understood the taxi clearance. He said that he did. I selected passenger announcement on my audio panel (which cuts out all radio reception on the copilot radio) and began the passenger announcement. As we approached the left runway we crossed the hold line and began to cross the runway. I assumed that we had been cleared across, until I observed a light plane rolling toward us after landing. The captain realized his mistake and increased power to clear the runway as quickly as possible. It turned out that we had never been cleared to cross, the captain had understood the clearance but he had 'forgotten' the hold short restriction and crossed the active runway anyway. No evasive action was taken by the other aircraft and it turned off well short of the intersection where we crossed. I don't believe he was ever aware that we were not cleared across the runway. There are times in all aircraft where one individual is almost completely responsible for the safety of flight while other crew members are performing other duties. It is incumbent upon this individual to exercise extreme vigilance during these times. I also feel that the workload placed on 2-PLT (no F/a) regional airline crews is extreme during the terminal phase of flight. If I could have been 'heads up' watching, instead of, 'off frequency' giving the passenger announcement this incident could have been entirely avoided.

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Original NASA ASRS Text

Title: COMMUTER LTT UNAUTH RWY CROSSING IN FRONT OF SMA LNDG ON PARALLEL RWY.

Narrative: TWO PARALLEL RWYS WERE IN USE, THE SMALLER LEFT RWY BY LIGHT ACFT AND THE LARGER RIGHT BY AIR CARRIERS. WE LANDED ON THE RIGHT WITH THE CAPT FLYING. WE CLRED THE RIGHT ON TXWY O AND WERE TOLD TO CONTACT GND. I CALLED GND AND WAS INSTRUCTED TO 'TAXI TO YOUR GATE VIA CHARLIE (WHICH CROSSES THE LEFT RWY AT A 45 DEG ANGLE AT MID-RWY) HOLD SHORT OF THE LEFT'. WE COMPLETED THE AFTER LNDG CHECKLIST AND THE CAPT BEGAN TO TAXI. I ADVISED THE CAPT THAT I WAS GOING TO MAKE THE PAX ANNOUNCEMENT AND ASKED IF HE UNDERSTOOD THE TAXI CLRNC. HE SAID THAT HE DID. I SELECTED PAX ANNOUNCEMENT ON MY AUDIO PANEL (WHICH CUTS OUT ALL RADIO RECEPTION ON THE COPLT RADIO) AND BEGAN THE PAX ANNOUNCEMENT. AS WE APCHED THE LEFT RWY WE CROSSED THE HOLD LINE AND BEGAN TO CROSS THE RWY. I ASSUMED THAT WE HAD BEEN CLRED ACROSS, UNTIL I OBSERVED A LIGHT PLANE ROLLING TOWARD US AFTER LNDG. THE CAPT REALIZED HIS MISTAKE AND INCREASED POWER TO CLEAR THE RWY AS QUICKLY AS POSSIBLE. IT TURNED OUT THAT WE HAD NEVER BEEN CLRED TO CROSS, THE CAPT HAD UNDERSTOOD THE CLRNC BUT HE HAD 'FORGOTTEN' THE HOLD SHORT RESTRICTION AND CROSSED THE ACTIVE RWY ANYWAY. NO EVASIVE ACTION WAS TAKEN BY THE OTHER ACFT AND IT TURNED OFF WELL SHORT OF THE INTXN WHERE WE CROSSED. I DON'T BELIEVE HE WAS EVER AWARE THAT WE WERE NOT CLRED ACROSS THE RWY. THERE ARE TIMES IN ALL ACFT WHERE ONE INDIVIDUAL IS ALMOST COMPLETELY RESPONSIBLE FOR THE SAFETY OF FLT WHILE OTHER CREW MEMBERS ARE PERFORMING OTHER DUTIES. IT IS INCUMBENT UPON THIS INDIVIDUAL TO EXERCISE EXTREME VIGILANCE DURING THESE TIMES. I ALSO FEEL THAT THE WORKLOAD PLACED ON 2-PLT (NO F/A) REGIONAL AIRLINE CREWS IS EXTREME DURING THE TERMINAL PHASE OF FLT. IF I COULD HAVE BEEN 'HEADS UP' WATCHING, INSTEAD OF, 'OFF FREQ' GIVING THE PAX ANNOUNCEMENT THIS INCIDENT COULD HAVE BEEN ENTIRELY AVOIDED.

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.