ATC center controller reported an aircraft descended below the minimum IFR altitude and reported a T...

Narrative:

Aircraft X responded to a TCAS RA that he thought was erroneous and returned to airport on a visual approach. There was no traffic observed on the radar [at] the time of the event; nor was there any observed traffic within 10 minutes before and after the event. Aircraft X did refer to himself as [an incorrect flight number] a few times while communicating. It took me a minute to realize it was him calling; because I initially thought aircraft X was trying to pick up IFR. I did verify that the aircraft was VMC with terrain and the airport in sight before issuing the visual approach because he had descended below the [minimum IFR altitude]. I also informed him the minimum IFR altitude was 5000 feet.

Original NASA ASRS Text

Title: ATC Center Controller reported an aircraft descended below the Minimum IFR Altitude and reported a TCAS/RA while there appeared to be no traffic in the area.

Narrative: Aircraft X responded to a TCAS RA that he thought was erroneous and returned to airport on a visual approach. There was no traffic observed on the radar [at] the time of the event; nor was there any observed traffic within 10 minutes before and after the event. Aircraft X did refer to himself as [an incorrect flight number] a few times while communicating. It took me a minute to realize it was him calling; because I initially thought Aircraft X was trying to pick up IFR. I did verify that the aircraft was VMC with terrain and the airport in sight before issuing the visual approach because he had descended below the [minimum IFR altitude]. I also informed him the minimum IFR altitude was 5000 feet.

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	1561312
Time
Date	201807
Local Time Of Day	1201-1800
Place
Locale Reference	ZAN.ARTCC
State Reference	AK
Aircraft 1
Make Model Name	Dash 8 Series Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

ATC center controller reported an aircraft descended below the minimum IFR altitude and reported a TCAS/RA while there appeared to be no traffic in the area.