Small Aircraft
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 75; Flight Crew Total 14000
Situational Awareness; Confusion; Communication Breakdown
ATC Issue All Types; Aircraft Equipment Problem Less Severe; Airspace Violation All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Landing Without Clearance
General None Reported / Taken
Aircraft; Human Factors; Environment - Non Weather Related
Due to a radio/intercom switch issue; coupled with expectation bias with which I made the assumption that the ZZZ Tower was closed; I ended up landing at ZZZ without radio contact with the Tower.The flight was VFR from ZZZ1 to ZZZ routing over ZZZ2. Flying over ZZZ2; I listened on the ATIS frequency and heard no letter identifier with the weather information because the Tower closed early (XA00L from NOTAM versus XF00L from airport directory). I made my area report on the Tower frequency as I flew over; using it as a CTAF. There was another aircraft that was working in the pattern; making reports on the CTAF; as well. I recall thinking that the COVID-19 crisis had even reached State X; where the Tower was closed early.Approaching ZZZ; I monitored on COMM2 what I thought was an ATIS frequency (only to realize later that it was an ASOS frequency) and of course; got no letter identifier with the weather information. This started me down the path to assuming that perhaps ZZZ Tower had closed early; like ZZZ2. With all the irregularities occurring around the world due to the COVID-19 crisis; it seemed reasonable.I then switched to COMM1 and made a radio call to Tower on Tower frequency; receiving no answer. Because there was no letter identifier on what I had thought was an ATIS frequency and no apparent answer after repeated queries to Tower; I assumed the Tower was closed and made my normal position reports; entering the pattern as if it was an uncontrolled field; using the CTAF frequency. What I did not realize is that I was neither receiving or transmitting on COMM1. The switches on the intercom panel were sticking and I failed to verify the transmit light; relying merely on the tactile touch of the button.There was no other traffic at ZZZ and I landed uneventfully. The airport appeared deserted; which only seemed to confirm my impression that the tower must have closed early due to the COVID-19 crisis. I parked the aircraft and it was not until two days later when departing did I realize that I had not been transmitting over COMM1 due to a switch problem and that the Tower had not been closed; but had still been in operation the night I landed.What contributed to this incident was my bias to assume the Tower had closed early like the Tower at ZZZ2. The fact that I did not hear the expected letter identifier that I am accustomed to at a Tower airport when I listened to ASOS--thinking it was ATIS--kept me going down this path of assumption. And then when I could not raise Tower; that seemed to only verify my assumptions. These assumptions prevented me from checking the radio switches when I did not receive a reply from the Tower and I instead continued to transmit as if at an uncontrolled field; not realizing that I was neither transmitting nor receiving.If I had not been operating under my false assumption; for example; if I was at my home field where I knew the tower was open and I was not getting a reply to my queries; I would have checked the intercom switches more carefully; tried a different frequency; or otherwise worked a potential radio issue. Instead; I attributed what was actually a radio issue to; 'Oh; Tower must be closed due to COVID.'As far as the switch issue; a qualified A&P mechanic has addressed it and the same issue should not happen again. This was a wake-up call for me. As a professional pilot; I fly around the world. In this new COVID-19 world; it was easy to chalk up irregularities to the 'new normal.' As aviators; we cannot ever allow ourselves to stray from our normal procedures and protocols. This incident painfully reminded me of the need to constantly check my assumptions.
Pilot reported landing without clearance due to a sticky radio switch and lack of incoming radio transmission; and thinking the Tower was closed due to COVID-19.