Date: 202010
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Aircraft: Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Operating under: Part 91
Flight plan: VFR
Flight phase: Landing
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Distraction; Fatigue; Situational Awareness; Confusion; Communication Breakdown
Second reporter function: Supervisor / CIC
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Detector: Person Other Person
Result: General None Reported / Taken
Contributing factors: Airport; Human Factors; Procedure
Primary problem: Human Factors

Narrative: I took sector X/Y/Z shortly after Aircraft X checked in from ZZZ Approach headed to ZZZ airport. I switched Aircraft X from frequency to different frequency. Usually when I switch an aircraft or they check in I would normally ask them to advise when they have the weather and issue any NOTAMs. I do not know why I did not ask this VFR aircraft if he had the weather or advise him of the PPR (Prior Permission Required). This is something very uncharacteristic of me. I did call traffic to Aircraft X twice before sending him to advisories and terminating his flight following. I generally treat VFR the same as IFR with regards to weather and NOTAMs. The aircraft apparently landed without calling into the airport and missed the trucks on the runway. My only conclusion is that the memory jogger for the airport 10 minute PPR was not next to the airport on the scope; it was quite a bit north of the airport. We also have a lot of other things written on the scope at this time with all the TFRs in the area. I did have several other things that required coordination and switching of frequency transmitter sites at the time but traffic was not that busy. Aircraft Y was orbiting in the TFR just outside of approach and was going to be a factor with another aircraft descending into ZZZ.I do remember being mentally exhausted from the day. We are continually forced to work combined sectors with a lot of frequency congestion; a lot of moving aircraft from frequency to frequency. Missing numerous TFRs and traffic orbiting the TFRs and listening to pilot readbacks on complex clearances. Lots of VFR aircraft with many traffic calls and aircraft not listening. We are busy in our area and keeping sectors split is not a priority. We just end up making things work and pushing through it. While this is not an excuse for why I did not do my job and issue the NOTAM I do believe it is contributing to the event in the long run.We need to return to normal staffing. We need to have sectors split out more. Ultimately we are straining our people and causing unnecessary stress in how we are currently running the area.


Second narrative: I assumed the CIC desk at XA:47. At XA:55 a runway incursion took place with a VFR Aircraft X who was not notified of the ten minute prior permission required for landing at ZZZ. I was unaware the incident took place until the next day. I was confident that the airspace wasn't too busy or complex for the configuration.Prior permissions for landing at ZZZ are very commonplace. The written note on the radar scope to remind us of the closure may be causing oversight because we see it so often. Perhaps we can change our way of indicating the closure using the draw function so it stands out more in our scan.


Synopsis: Center Controllers reported an aircraft landing at an airport where the runway was closed.