Date: 202011
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Small Aircraft
Operator: FBO
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Final Approach
Airspace: Class G ZZZ
ATC / advisory: CTAF ZZZZ
Reporter organization: Personal
Reporter function: Instructor; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Commercial
Human factors: Situational Awareness
Second reporter function: Pilot Flying; Trainee
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Environment - Non Weather Related; Human Factors; Procedure; Airport
Primary problem: Human Factors

Narrative: ZZZ Tower was closed due to mandatory cleaning when a Controller tested positive. The airport was operating under CTAF frequency. We got the ATIS after pattern work at ZZZ1; then decided to shoot the RNAV XX; with the winds reporting 300 @ 12 knots. We contacted approach and got vectors for the RNAV XX. After being switched over to the CTAF frequency from Approach; we heard multiple aircraft utilizing Runway XYR. With the traffic using Runway XYR we decided it would be best to circle to Runway XYR; since a circle to Runway XYL is NA per the approach plate. When reaching circling minimums and within the circling radius we began to circle east of the field on a left base to Runway XYR. This required us [to] cross over the extended centerline of [Runway] XYL. We flew the rest of the pattern and landed with no incident or traffic conflict. Additionally; no traffic was in the pattern for [Runway] XYL at the time and no traffic was affected by this decision.I believe that the other traffic using Runway XYR instead of Runway XX (based on what the wind was calling) was a huge factor. My student and I were concerned on entering right traffic for Runway XYR and overflying the field roughly 1;480 MSL/600 AGL feet above and potentially creating a traffic conflict for those operating on [Runway] XYR. This is what drove us to make left traffic for Runway XYR.


Second narrative: I was flying the RNAV XX into ZZZ with CFI (Certified Flight Instructor). ZZZ Tower was closed early due to mandatory cleaning after Controller tested positive for COVID-19. Airport was operating under CTAF frequency. After checking ZZZ ATIS after pattern work at ZZZ1; the decision was made to shoot the RNAV XX into ZZZ as winds were 300@12. Contacted Approach; who granted us the approach clearance. Upon switching to ZZZ CTAF; it became clear that traffic was using [Runway] XYR/L despite the winds favoring Runway XX. We made the decision to break off the approach at CAT B circling minimums and circle to [Runway] XYR as a circle to [Runway] XYL from RNAV XX is NA per the approach plate. This required us to cross over the extended centerline of [Runway] XYL. We circled east of the field and entered a left base for Runway XYR and proceeded to fly a normal pattern with no incident or traffic conflict.If we were to fly right traffic instead for Runway XYR that would have required us to cross midfield at 1;480 MSL (approximately 600 FT AGL); which could create a potential conflict for traffic on go-around/missed. Rather; we elected to essentially perform a circle [Runway] XYL with a sidestep to [Runway] XYR (as the circle to land [Runway] XYL from [Runway] XX is NA). Additionally; no traffic was affected by this decision.


Synopsis: Flight Instructor and student reported conducting a circle to land approach to a runway which resulted in crossing over the extended centerline of the parallel runway. The crew stated the Tower was closed for COVID-19 cleaning.