Date: 202007
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Communication Breakdown; Human-Machine Interface
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Environment - Non Weather Related; Human Factors; Procedure
Primary problem: Human Factors

Narrative: I was pilot flying on Aircraft X from ZZZZ-ZZZ. The whole flight was uneventful and well within standards until the end of arrival/beginning of approach into ZZZ. There was a TFR that was lifted immediately before our arrival which I suspect complicated sequencing for ATC. We were instructed to expect a visual approach to XXL and to remain at 8;000 feet on a 290 heading over the southern foothills. This was expected to be a double-downwind type vector to aid in sequencing due to the VIP departure minutes ago. On this heading; abeam the airport at 8;000 feet we were suddenly instructed to fly a heading of 030 and shortly thereafter were offered Runway XY. As part of the in range briefing the Captain and I decided that we would be willing and able to accept a late runway change as long as we could dial up the localizer in time and the conditions were generously VMC. This being the case; we accepted a clearance for a visual approach to Runway XY. Being so high in such tight proximity to the airfield; I immediately selected 3;000 feet for the final approach fix; began a rapid descent and began vectoring us for a stable visual approach. It suddenly became clear that I would need to deploy the flight spoilers to aid in the descent and I did so. This was shortly followed by IB and OB Spoilerons caution message. At this time we were on roughly a 10 mile left base for Runway XY and the Captain was programming the FMS for the ILS XY. I had the XY localizer tuned and verified; so additional guidance from the FMS would serve as an aid to situational awareness. As we recall; we were on approach frequency (XYZ.A) at the time; and were told to contact north Tower on XXB.C. In the task saturated environment; XXB.BC was tuned in error. I managed to get us set up for a stable approach well outside the final approach fix; but being so occupied in this task; I failed to recognize that the incorrect Tower frequency was tuned. I disconnected the autopilot well outside the final approach fix as I deemed it necessary to practice hand flying skills. We continued with a stable approach to an uneventful landing. As we were vacating the runway I realized the frequency error and immediately tuned to XXB.C and notified the Tower Controller that we were vacating the runway. The Controller replied with 'How do you hear this transmitter?' to which I replied 'Loud and clear.' This error would have made the receipt of a landing clearance impossible; although we unanimously recalled that we were cleared to land. A classic example of expectation bias. We were then issued taxi instructions to the ramp. No phone number was issued and nothing was mentioned about any failure to receive a landing clearance or other inconveniences resulting thereof. We then taxied to the gate and shut down uneventfully. During these current times we (reserve pilots) are somewhat rusty and; as a result; less able to manage such a high level of task saturation that would otherwise be easily conquered. The factors that contributed to task saturation were: Being left high and close to the airport with tight vectors; the runway change and subsequent FMS programming; IB/OB Spoilerons Caution message; and turbulent/windy surface conditions requiring a high degree of focus on hand flying a stable approach. I struggle to see a viable remedy for this problem besides just flying more; which the current situation may or may not allow soon. The only thing we could have done differently would be to refuse the visual approach to XY and rather continue to XXL as was programmed and briefed. However we both felt comfortable with and briefed that we would be willing to accept a late change to XY. Furthermore; an approach to XXL would have been even shorter; possibly even acting to worsen the task saturated condition. Expectation bias contributed to the possibility of landing without a clearance; it's as simple as that. We both agreed that we were cleared to land; so a review of the tapes would be required to determine the exact nature of the exchange. It seems to me that those of us who haven't been flying recently simply need to re-acquaint ourselves with a newly degraded level of proficiency; and should be increasingly alert of events that could lead to task saturation and the errors that can result.


Second narrative: First Officer was the pilot flying and I was the pilot monitoring. We were flying Aircraft X from ZZZZ-ZZZ. The flight went smoothly until the approach into ZZZ. ATC was busy due to VIP movement. We were initially expecting a visual approach to Runway XXL and to remain at 8;000 feet on heading 290. ATC needed to sequence us due to VIP movement departing the airport. We then were instructed to fly heading 030 to put us on the left downwind for Runway XXL. After this; it became apparent that there was spacing for us for Runway XY so ATC asked us if we wanted Runway XY. I questioned the First Officer during the In-Range Checklist about if he would feel comfortable with a sudden change in runway from XXL to Runway XY. He stated; 'Yes.' I accepted the clearance from XYZ.DZ for a visual approach to Runway XY; which was close proximity to the runway; but there was adequate spacing to make sure the approach was stable and safe. Tower told us to switch to XXB.CZ. The First Officer selected 3;000 feet in the altitude preselect and we started to get configured to land. He was slightly fast and high; so he decided to use the flight spoilers. Shortly thereafter; the IB Spoilers and IB Spoilerons Caution message appear. We ran the QRH and continued to land. The landing was within standards with no issues. After vacating the runway; the First Officer noticed that we were on frequency XXB.BC and not on XXB.CZ. During the high task saturated environment; the wrong frequency was tuned in error. First Officer selected XXB.CZ and Tower asks us; 'How do you hear this transmission?' The First Officer replied; 'Loud and Clear.' We then were issued taxi instructions to the ramp. Tower and Ground did not provide a phone number for us to call and nothing was mentioned about any failure to receive a landing clearance. We taxied to the ramp to the gate with no issues.During the current state that we are facing; many pilots including reserve pilots are a little rusty due to not flying. The last time I flew before this flight was two months ago. The First Officer told me in our initial meeting that he hadn't flown for 6 weeks. We were/are aware that our proficiency level decreases as we are not flying as much. Factors including task saturation; IB Spoilers and IB Spoilerons Caution message; FMS programming; turbulent; windy conditions. I truly believe that if we were flying more; this normal approach would not have been an issue. In my initial briefing with the First Officer I even discussed this and made a point to let him know that I was a newer Captain and hadn't flown for two months. I did complete 90 day currency on [date] in the simulator. Maybe during these times; it would have been better to stay on Runway XXL to decrease workload until a time that we feel more proficient and are flying more. We definitely need to be more aware of how much our proficiency decreases as we are flying less.


Synopsis: Air carrier flight crew reported landing without a clearance after dialing in the incorrect frequency.