Date: 201211
Local time of day: 1201-1800
Location: PCT.TRACON, VA
Aircraft: Skylane 182/RG Turbo Skylane/RG
Flight plan: IFR
Flight phase: Cruise
ATC / advisory: TRACON PCT
Second aircraft: M-20 Series Undifferentiated or Other Model
Reporter organization: Government
Reporter function: Approach; Departure
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I was working BELAY and Aircraft X departed BWI. The aircraft was handed to me from WOOLY Sector. The aircraft appeared to be a normal IFR track. The flight progress strip however had an equipment suffix of X and had no beacon code assigned. The track had a locally assigned code.  This confused me because 90 percent of Aircraft X flights I have worked fly VFR. It was a VFR day. Based on the strip; I treated the aircraft as IFR and cleared him to his destination and climbed him to the requested altitude on the strip. We work with no assistant. We have one Flight Data Controller. My Flight Data Controller was having a social conversation with a Controller at a far away scope. I needed a computer generated code to automate the hand off with HAR Approach; so I had to walk away from my scope to the data position and amended the equipment type. When I returned; I terminated the track so it would auto acquire with the new code. I then had to go to flight data position to make several 6-10 amendments on VFR aircraft; as our Data Controller was still distracted. Aircraft X never auto acquired and I had several other aircraft that called. So; now I had forgotten about Aircraft X. Aircraft Y was at 6;000 FT and being vectored toward his destination southbound. A flight of 2 military jets departed MTN northbound needing a climb to 7;000 FT; so I descended Aircraft Y to 4;000 FT. When I saw the 'splat tag' that I instantly remembered was Aircraft X; I immediately saw he was in conflict with Aircraft Y and converging. I think the aircraft were about 2 miles apart and 500 FT and Aircraft Y was descending. I couldn't remember Aircraft X's flight number; because I had left the strip at the data console. So I turned Aircraft Y to the east and issued traffic. I then turned Aircraft X northbound and issued traffic. I issued subsequent traffic calls to each aircraft. Aircraft X then reported traffic in sight. The remainder of the session was uneventful. Someone (BWI Tower?) had to manually assign Aircraft X a beacon code. They should understand that this causes more trouble for the Departure Controller as we have to either complete a manual hand off; or assign a computer code. The latter of those two requires much effort to get the new track to acquire and automate properly. It also requires we drop the track which is one of the most dangerous things we do; because it is very easy to get distracted and forget about a 'splat' tag. Our flight data position (which is really two positions combined) is rarely split. The supervisors also rarely reign in distracted data controllers; who often wonder off; or have side conversations instead of working their assigned position. This requires controllers walk 5-10 feet from their scopes; with their backs turned and make 6-7-10 and other laborious data entries. This is dangerous and it happens on a daily basis in my area. I did not follow one of my cardinal rules; which is never leave a 'splat' tag. If it doesn't auto acquire; start a manual track.




Synopsis: PCT Controller experienced a loss of separation event when leaving the RADAR control position to modify a flight plan; the Flight Data Controller otherwise engaged in another location.