Date: 201505
Local time of day: 1801-2400
Location: S46.TRACON, WA
Light: Dusk
Aircraft: Small Aircraft; Low Wing; 2 Eng; Retractable Gear
Flight plan: VFR
Flight phase: Cruise
Airspace: Class D TCM
ATC / advisory: TRACON S46
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Distraction; Situational Awareness
Anomaly: Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: I assumed the Positions of Arrival West (W); Arrival East (E) and Boeing Final (O).  I was briefed about a Aircraft X flying around the local area.  It appeared he was in South Satellite's Airspace (N) or Final (F); more than he was mine.  But I assumed the area he was going to be working was mostly gonna be my Airspace.  I assumed the position and looked over a sheet that had the aircraft's call sign on it and a Map of our local area.  It failed to state what route the aircraft was actually flying and at no point did the aircraft advise me of his route or when he was on station or changing positions.  He was mostly tracking a north/south route along our final as we were in a north flow at SeaTac (SEA). At this point I started to get busy with Arrival Traffic at SEA; arrival traffic into Boeing (BFI); arrival traffic into Renton (RNT) on a GPS circle approach which was a conflict with my BFI Traffic and I was having to coordinate a sequence with departure east (A); which had the RNT aircraft and arrival traffic going into Auburn (S50) on a GPS approach.  At this point in time Aircraft X started to work further south west.  I was distracted with everything else going on and failed to notice that he had penetrated McChord Air Force Base's (TCM) Class D Airspace. At this point the CIC came over and said that McChord might have some activity going on at their airport and to ensure I got a point out with their tower.  At that time I realized he was much more N's airspace than mine; so I attempted an automated hand off to N and I called TCM and notified them of his activity. After getting off the line; N Called me back and said McChord Tower wanted to talk to the aircraft.  So I said I was just on the line with them; they want him?  The N Controller said yes; so at that point the N controller flashed the aircraft to TCM; they took the handoff.  We discussed which frequency they wanted him on and I transferred the aircraft to TCM Tower.  I was relieved off of position a few minutes later and told that the aircraft had penetrated the TCM Class D airspace. I would say De-Combining Positions would have certainly helped in this scenario.  I was too occupied with other traffic in other areas to provide quality service and flight following to this aircraft.  Also; I should have handed this aircraft off to N sooner; maybe their work load would have been less and they would have had time to point the aircraft out prior to him entering the TCM Class D.  Also; I should have asked for help on figuring out what the aircraft's intended route of flight actually would be; either from the aircraft himself or management.  I kept reviewing the paper thinking I was missing something and didn't see any route markings; certainly had no idea he would be penetrating any Class D Airspace.




Synopsis: An S46 Controller reports of working an aircraft and then getting busy with other traffic. The aircraft enters Class Delta Airspace and the Controller fails to notice this. The Controller was working combined airspace and this aircraft was inside another Controller's airspace and not handed off to him.