Narrative:

When I had taken the ground control [ground control] position; runway 03/21 had just been returned to ground control after a small arrival to the runway. Runway 03/21 is typically used by ground control unless prior coordination usually when traffic permits a small prop to land on it and [local control] LC2 requests use of it from ground control. LC2 had requested the use of runway 03/21 for another arrival no more than 15 minutes after I took the position. I; working ground control had also [clearance delivery] clearance delivery/FD combined with me; so I had multiple things taking my attention. I authorized the use of 03/21. Aircraft X had called for taxi and I gave them standard routing for the flow we were in; 'runway 10L; taxi via tango; kilo; cross runway 21.' I had forgotten that I had given 03/21 to LC2 position. The other local control had come over and was standing next to me which I thought was strange and I made a comment to why he was there and he drew my attention the fact that aircraft X was crossing the departure end of RWY03 and aircraft Y was short final for that runway on the opposite end. The LC2 controller was made aware of the situation at the same time. We observed that aircraft X had been clear of the runway edge before aircraft Y crossed the landing threshold. In air traffic control; we can't always rely on our memories - there is too much at stake for that. That is why we have memory aids that we utilize. I was using a memory aid when this occurred and my scan had failed me. I had gotten into a flow that is more common and rattled off a standard instruction without giving a second thought to it. In order to prevent this situation from occurring again; I need to utilize my good scanning techniques that have saved situations from happening in the past. By doing this; I would have seen the memory aid and could have and will prevent this from happening in the future.

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Original NASA ASRS Text

Title: Portland Tower Ground Controller reported crossing an aircraft; while the Local Controller had an aircraft on final.

Narrative: When I had taken the GC [Ground Control] position; RWY 03/21 had just been returned to GC after a small arrival to the runway. RWY 03/21 is typically used by GC unless prior coordination usually when traffic permits a small prop to land on it and [Local Control] LC2 requests use of it from GC. LC2 had requested the use of RWY 03/21 for another arrival no more than 15 minutes after I took the position. I; working GC had also [Clearance Delivery] CD/FD combined with me; so I had multiple things taking my attention. I authorized the use of 03/21. Aircraft X had called for taxi and I gave them standard routing for the flow we were in; 'RWY 10L; taxi via Tango; Kilo; Cross RWY 21.' I had forgotten that I had given 03/21 to LC2 position. The other LC had come over and was standing next to me which I thought was strange and I made a comment to why he was there and he drew my attention the fact that Aircraft X was crossing the departure end of RWY03 and Aircraft Y was short final for that runway on the opposite end. The LC2 controller was made aware of the situation at the same time. We observed that Aircraft X had been clear of the runway edge before Aircraft Y crossed the landing threshold. In air traffic control; we can't always rely on our memories - there is too much at stake for that. That is why we have memory aids that we utilize. I was using a memory aid when this occurred and my scan had failed me. I had gotten into a flow that is more common and rattled off a standard instruction without giving a second thought to it. In order to prevent this situation from occurring again; I need to utilize my good scanning techniques that have saved situations from happening in the past. By doing this; I would have seen the memory aid and could have and will prevent this from happening in the future.

Data retrieved from NASA's ASRS site 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.