Narrative:

Arriving in sea they were landing 34C and 34L and they were taking off on 34R. This stuck in my mind and helped lead to an error later. On departure preflight and pushback were normal and uneventful. We contacted ground and our taxi clearance; as best as I can recall was; 'taxi to runway 34C via bravo and quebec.' the first officer read it back and I verbalized the clearance. We were planning on 34R so the first officer went 'heads down' to get the new takeoff data and program the FMC for the new RNAV departure points. I taxied intentionally slowly to give him time to get everything done. Approaching 34R I verbalized that I was crossing 34R and the first officer questioned whether we were cleared to cross and I said we were. At that same time sea ground told us to monitor tower. I checked final and saw an aircraft on final but thought it was on approach to 34C. I proceeded across 34R and about halfway across tower sent the aircraft on final around. While holding short of 34C; tower asked us to call for a possible pilot deviation. We were then cleared for takeoff and proceeded to our destination uneventfully. I called the number the tower gave us. The gentleman who answered said he had reviewed the tapes and said we were told to hold short of 34R and we read it back. Neither the first officer nor I recall any instructions to hold short 34R. He said there was never a loss of separation. He then proceeded to take my personal information and advised me he would be filing paperwork. When we received the taxi clearance to 34C; I thought 34R must be closed because that's the standard departure runway. I know we cannot cross an active runway enroute to our departure runway; but I thought 34R must be closed and therefore we could cross and proceed to 34C. That was obviously not the case. I do not recall what the ATIS was reporting as the departure runway. I should have stopped the aircraft and allowed the first officer to complete his programming duties in a no threat enviroment instead of continuing the taxi. Additionally; when the first officer questioned whether we were cleared to cross; I should have stopped the aircraft and checked with the tower. I don't recall being instructed to hold short 34R or verbalizing it back to the first officer; although even without being specifically instructed to hold short 34R; we should have since it was an active runway.

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Original NASA ASRS Text

Title: An air carrier Flight Crew described a runway incursion in SEA that led to a go-around.

Narrative: Arriving in SEA they were landing 34C and 34L and they were taking off on 34R. This stuck in my mind and helped lead to an error later. On departure preflight and pushback were normal and uneventful. We contacted Ground and our taxi clearance; as best as I can recall was; 'Taxi to Runway 34C via Bravo and Quebec.' The First Officer read it back and I verbalized the clearance. We were planning on 34R so the First Officer went 'heads down' to get the new takeoff data and program the FMC for the new RNAV departure points. I taxied intentionally slowly to give him time to get everything done. Approaching 34R I verbalized that I was crossing 34R and the First Officer questioned whether we were cleared to cross and I said we were. At that same time SEA Ground told us to monitor Tower. I checked final and saw an aircraft on final but thought it was on approach to 34C. I proceeded across 34R and about halfway across Tower sent the aircraft on final around. While holding short of 34C; Tower asked us to call for a possible Pilot Deviation. We were then cleared for takeoff and proceeded to our destination uneventfully. I called the number the Tower gave us. The gentleman who answered said he had reviewed the tapes and said we were told to hold short of 34R and we read it back. Neither the First Officer nor I recall any instructions to hold short 34R. He said there was never a loss of separation. He then proceeded to take my personal information and advised me he would be filing paperwork. When we received the taxi clearance to 34C; I thought 34R must be closed because that's the standard departure runway. I know we cannot cross an active runway enroute to our departure runway; but I thought 34R must be closed and therefore we could cross and proceed to 34C. That was obviously not the case. I do not recall what the ATIS was reporting as the departure runway. I should have stopped the aircraft and allowed the First Officer to complete his programming duties in a no threat enviroment instead of continuing the taxi. Additionally; when the First Officer questioned whether we were cleared to cross; I should have stopped the aircraft and checked with the Tower. I don't recall being instructed to hold short 34R or verbalizing it back to the First Officer; although even without being specifically instructed to hold short 34R; we should have since it was an active runway.

Data retrieved from NASA's ASRS site as of April 2012 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.