Narrative:

I was working on arrival sector and we had just combined the high sector with the low sector. Normal traffic and weather. I had [aircraft X] landing on frequency and had cleared him to cross the fix at 10;000 feet. I also was working [aircraft Y] who was landing at an uncontrolled airport within the sector. At [aircraft Y] reported airport in sight and cancelled IFR. The computer I.D. (Cid) for [aircraft Y] was 641 and the cid for [aircraft X] was 651. When I did a remove strip for [aircraft Y] I typed in the cid for [aircraft Y] and 'fat fingered' the keypad and inadvertently typed in 651 instead of 641 which in turn dropped the flight plan on [aircraft X]. I then went to issue a clearance to another aircraft and noticed I still had the radar data tag for [aircraft Y]. I thought I must have missed hitting enter the first time so I re-entered the remove strip command and successfully dropped the flight out of the computer. I was relieved and issued a position relief briefing. Not seeing that I had inadvertently dropped the flight plan on [aircraft X] the relieving controller was not aware of the target and he entered TRACON airspace without a handoff.my own personal solution which I have already instituted is to never use keyboard to enter a cid on a flight plan removal. If I remove a flight plan it should be done with a track ball pick.

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Original NASA ASRS Text

Title: An aircraft cancelled IFR and services. The Controller removed the flight plan from the system using the three number Computer I.D. The controller inadvertently entered the wrong number which was for another aircraft in his sector. The Controller did not notice the Radar Data Tag drop off the target and forgot about the aircraft. The aircraft entered the adjacent TRACON airspace without a handoff or any coordination.

Narrative: I was working on arrival sector and we had just combined the high sector with the low sector. Normal traffic and weather. I had [Aircraft X] landing on frequency and had cleared him to cross the fix at 10;000 feet. I also was working [Aircraft Y] who was landing at an uncontrolled airport within the sector. At [Aircraft Y] reported airport in sight and cancelled IFR. The Computer I.D. (CID) for [Aircraft Y] was 641 and the CID for [Aircraft X] was 651. When I did a remove strip for [Aircraft Y] I typed in the CID for [Aircraft Y] and 'fat fingered' the keypad and inadvertently typed in 651 instead of 641 which in turn dropped the flight plan on [Aircraft X]. I then went to issue a clearance to another aircraft and noticed I still had the radar data tag for [Aircraft Y]. I thought I must have missed hitting enter the first time so I re-entered the remove strip command and successfully dropped the flight out of the computer. I was relieved and issued a position relief briefing. Not seeing that I had inadvertently dropped the flight plan on [AIRCRAFT X] the relieving controller was not aware of the target and he entered TRACON airspace without a handoff.My own personal solution which I have already instituted is to never use keyboard to enter a CID on a flight plan removal. If I remove a flight plan it should be done with a track ball pick.

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.