Narrative:

I received a clearance from portland ground control to taxi from the ramp to runway 10L for takeoff. The following clearances in quotations are as close to true quotes as I can recall. I received the following clearance: 'taxi runway 10L via E4; east; hold short runway 10R'. I read back the clearance and taxied as instructed. The next taxi clearance was: 'cross runway 10R; turn left; taxi north on runway 3 to 10L'. I held my position and asked the controller if he wanted me to cross runway 10R then turn left on B taxiway to get to runway 3 and then proceed north to 10L. The controller replied 'no'. He then said 'cross runway 10R; take a little left; and taxi on runway 3 for 10L'. I read back 'cross 10R then left onto 3 to taxi 10L' and proceeded to cross 10R. I did not realize the there was a dash 8 holding short of 10R on the north side of the runway on taxiway east. The dash 8 had its taxi light on the entire time ground control and I were talking to one another; it was dark and rainy; and so I thought the dash 8 was much farther north on taxiway east; taxiing southbound. Once I got to the north side of 10R I realized how close the dash 8 was and taxied around it; turned left onto B; right onto runway 3 and finally to 10L. I knew that was not the plan in the controller's mind but I did it in order to get out of the way and onto runway 3. I had taxied without fully understanding how the controller wanted me to transition from taxiway east to runway 3. Vague taxi instructions; darkness and rain and the lack of depth perception that produced; and my desire to cooperate with the controller all contributed to the mishap. Next time I do not understand a taxi clearance in its entirety I will not move my aircraft until I do. I should not have acted so hastily. I should have had less regard for maintaining traffic flow and more regard for clear communication and accurate execution of my taxi instructions.

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Original NASA ASRS Text

Title: A nighttime breakdown in communications between the flight crews of two aircraft; the local controller and the ground controller resulted in a runway and taxiway incursion and a ground conflict between the two aircraft.

Narrative: I received a clearance from Portland Ground Control to taxi from the ramp to Runway 10L for takeoff. The following clearances in quotations are as close to true quotes as I can recall. I received the following clearance: 'taxi Runway 10L via E4; E; hold short Runway 10R'. I read back the clearance and taxied as instructed. The next taxi clearance was: 'cross Runway 10R; turn left; taxi north on Runway 3 to 10L'. I held my position and asked the controller if he wanted me to cross runway 10R then turn left on B Taxiway to get to Runway 3 and then proceed north to 10L. The controller replied 'No'. He then said 'cross Runway 10R; take a little left; and taxi on Runway 3 for 10L'. I read back 'cross 10R then left onto 3 to taxi 10L' and proceeded to cross 10R. I did not realize the there was a Dash 8 holding short of 10R on the north side of the runway on Taxiway E. The Dash 8 had its taxi light on the entire time Ground Control and I were talking to one another; it was dark and rainy; and so I thought the Dash 8 was much farther north on Taxiway E; taxiing southbound. Once I got to the north side of 10R I realized how close the Dash 8 was and taxied around it; turned left onto B; right onto Runway 3 and finally to 10L. I knew that was not the plan in the controller's mind but I did it in order to get out of the way and onto Runway 3. I had taxied without fully understanding how the controller wanted me to transition from Taxiway E to Runway 3. Vague taxi instructions; darkness and rain and the lack of depth perception that produced; and my desire to cooperate with the controller all contributed to the mishap. Next time I do not understand a taxi clearance in its entirety I will not move my aircraft until I do. I should not have acted so hastily. I should have had less regard for maintaining traffic flow and more regard for clear communication and accurate execution of my taxi instructions.

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.