Narrative:

Tower/ground control instructed us to taxi to runway 11L at A4. The captain started to taxi and I went heads down to program the FMS. Then as I was briefing the departure, I discovered I didn't put maximum power in the FMS as was required due to the deice procedure just accomplished. I then selected maximum power which deleted our programmed takeoff v-spds. The captain trying to help then went heads down to reinsert the v-spds while I was doing other programming. I then looked up to see us crossing runway 3/21. This puzzled me because I thought our intersection A4 was prior to runway 3/21, but I was not very familiar with this airport and the captain was, although it had been some yrs since he'd been here. By this time we'd already crossed the runway. I told the captain that I thought we'd passed our intersection at about the same time that he realized it. We then got clearance from ground/tower (same person working both) to taxi back on runway 3/27 to runway 11L for takeoff. From now on, if the captain starts programming the FMS, I will go heads up and stop programming. Even though that programming is my duty, I may have been able to prevent an unauthorized runway crossing and potential disaster had I done that. I could also be more assertive in telling the captain that I will program, he should taxi. Supplemental information from acn 497965: on taxi out we were busy with the taxi checklist. A change to the FMC was required and I went heads down to input the change, which I should not have done. With the runway layout, I missed the turn at A4 and inadvertently crossed runway 21/3. At that time the ground controller authority/authorized a turn onto runway 21 and runway 11L.

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Original NASA ASRS Text

Title: A B734 CREW MISSED TURN TO TKOF RWY, CONTINUED AN UNAUTH TAXI ACROSS AN INTERSECTING RWY.

Narrative: TWR/GND CTL INSTRUCTED US TO TAXI TO RWY 11L AT A4. THE CAPT STARTED TO TAXI AND I WENT HEADS DOWN TO PROGRAM THE FMS. THEN AS I WAS BRIEFING THE DEP, I DISCOVERED I DIDN'T PUT MAX PWR IN THE FMS AS WAS REQUIRED DUE TO THE DEICE PROC JUST ACCOMPLISHED. I THEN SELECTED MAX PWR WHICH DELETED OUR PROGRAMMED TKOF V-SPDS. THE CAPT TRYING TO HELP THEN WENT HEADS DOWN TO REINSERT THE V-SPDS WHILE I WAS DOING OTHER PROGRAMMING. I THEN LOOKED UP TO SEE US XING RWY 3/21. THIS PUZZLED ME BECAUSE I THOUGHT OUR INTXN A4 WAS PRIOR TO RWY 3/21, BUT I WAS NOT VERY FAMILIAR WITH THIS ARPT AND THE CAPT WAS, ALTHOUGH IT HAD BEEN SOME YRS SINCE HE'D BEEN HERE. BY THIS TIME WE'D ALREADY CROSSED THE RWY. I TOLD THE CAPT THAT I THOUGHT WE'D PASSED OUR INTXN AT ABOUT THE SAME TIME THAT HE REALIZED IT. WE THEN GOT CLRNC FROM GND/TWR (SAME PERSON WORKING BOTH) TO TAXI BACK ON RWY 3/27 TO RWY 11L FOR TKOF. FROM NOW ON, IF THE CAPT STARTS PROGRAMMING THE FMS, I WILL GO HEADS UP AND STOP PROGRAMMING. EVEN THOUGH THAT PROGRAMMING IS MY DUTY, I MAY HAVE BEEN ABLE TO PREVENT AN UNAUTH RWY XING AND POTENTIAL DISASTER HAD I DONE THAT. I COULD ALSO BE MORE ASSERTIVE IN TELLING THE CAPT THAT I WILL PROGRAM, HE SHOULD TAXI. SUPPLEMENTAL INFO FROM ACN 497965: ON TAXI OUT WE WERE BUSY WITH THE TAXI CHKLIST. A CHANGE TO THE FMC WAS REQUIRED AND I WENT HEADS DOWN TO INPUT THE CHANGE, WHICH I SHOULD NOT HAVE DONE. WITH THE RWY LAYOUT, I MISSED THE TURN AT A4 AND INADVERTENTLY CROSSED RWY 21/3. AT THAT TIME THE GND CTLR AUTH A TURN ONTO RWY 21 AND RWY 11L.

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.