Center controller reported that an aircraft that did not display a radar data block flew through a c...

Narrative:

I was working combined sectors during a slow period. Not much was happening; when [another] sector controller asked me if I knew anything about the mode C intruder; labeled aircraft X. I didn't; and noticed that it was at 35;000 ft. Heading northwest bound. There was no flight plan information on this aircraft; so I called the [adjacent center sector] and asked them about it. They were unsure of what had happened; and since entering remove strip messages of the wrong aircraft has been common recently; I assumed that is what had happened.there is a good possibility that I saw the target and the data block; but did not register that the flight plan had been removed. This is a common corner of the sector to 'flash through' aircraft that just clip the corner. If there would have been traffic at 35;000 ft. I'm rather certain I would have seen this target. We also have frequent 'bad radar hits' in the sector where this event took place. It's common to see mode C intruders in the flight levels for a few hits before they disappear.I'm only a novice computer programmer; but it seems extremely simple to include in the code of the next eram (en route automation modernization) update an 'if statement' that does not allow a target to be removed if the mode C or assigned altitude is above 18;000 ft. Humans make mistakes. This appears to be a systemic issue that could easily be solved with a few lines of code.

Original NASA ASRS Text

Title: Center Controller reported that an aircraft that did not display a radar data block flew through a corner of the airspace without coordination.

Narrative: I was working combined sectors during a slow period. Not much was happening; when [another] Sector Controller asked me if I knew anything about the Mode C intruder; labeled Aircraft X. I didn't; and noticed that it was at 35;000 ft. heading northwest bound. There was no flight plan information on this aircraft; so I called the [adjacent Center Sector] and asked them about it. They were unsure of what had happened; and since entering remove strip messages of the wrong aircraft has been common recently; I assumed that is what had happened.There is a good possibility that I saw the target and the data block; but did not register that the flight plan had been removed. This is a common corner of the Sector to 'flash through' aircraft that just clip the corner. If there would have been traffic at 35;000 ft. I'm rather certain I would have seen this target. We also have frequent 'bad radar hits' in the sector where this event took place. It's common to see Mode C Intruders in the flight levels for a few hits before they disappear.I'm only a novice computer programmer; but it seems extremely simple to include in the code of the next ERAM (En Route Automation Modernization) update an 'IF statement' that does not allow a target to be removed if the MODE C or Assigned Altitude is above 18;000 ft. Humans make mistakes. This appears to be a systemic issue that could easily be solved with a few lines of code.

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.

Attributes
ACN	1757336
Time
Date	202008
Local Time Of Day	0001-0600
Place
Locale Reference	ZLC.ARTCC
State Reference	UT
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Large Transport
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 2
Events
Anomaly	ATC Issue All Types Airspace Violation All Types Deviation - Procedural Published Material / Policy

Center controller reported that an aircraft that did not display a radar data block flew through a corner of the airspace without coordination.