Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Communication Breakdown
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Human Factors
On approach to LWB while descending to 6;000 we were directed to go direct to the airport and call the airport when in sight and we then called the airport. We then both believed Washington cleared us for the visual approach to Runway 22. We had the RNAV 22 approach in the box at that time [and] I gave the First Officer direct to DENLE.The First Officer started his descent and passing through 5;200 ATC asked if we had the field in sight and we told him that we did. He replied back that his MVA was 6;000 feet for that area and that he had not cleared us for the visual. He then cleared us for the visual to Runway 22 and turned us over to [the] Tower. There was never a conflict with terrain or other traffic. Just a normal visual approach.[Due to] frequency congestion; work load; and [expectation bias] we may have missed part of his communication to us. After landing and discussing the situation we both thought he had cleared [us] for the approach. I need to have more situational awareness in the future and query ATC when there is a possible miscommunication.
On descent to LWB while descending to 6;000 with the autopilot engaged we were asked by Washington Center if we had the airport in sight. Captain (pilot monitoring) replied affirmative and we were told to go direct to the field. (We both believed we heard cleared for the visual approach). We had the RNAV GPS Runway 22 approach loaded in the FMS as a back up to our planned and briefed visual approach. The Captain selected direct to DENLE (FAF) and set the altitude select to 4;000 feet. I selected NAV and VNAV and the aircraft began its descent at a 3.0 degree top of descent point. At approximately 5;200 feet (800 below our original assigned altitude) ATC Controller asked if we had the field in sight and told us we had not been cleared for the visual approach yet and that we were currently below his MVA. We told the Controller we were in visual conditions and had the airport in sight. The Controller cleared us for the visual approach and we landed without event. Never during the descent of approach was terrain separation lost or did we ever receive a GPWS warning. This was a normal visual approach with the exception that we did not have an ATC clearance to descend.I need to listen better to what is actually said versus what we expect to hear. It is extremely unfortunate that both of us committed the same listening error. A very significant part of the safety of our ATC system is based on both pilots hearing the same thing. This fact is our checks and balances; our barrier to error. I was very aware of our altitude in respect to the approach and the fact that we needed to begin our descent. Our assignment to go direct the field and inquiry if we had the field in sight was at the correct time to start our descent for a normal visual 3.0 degree approach. This fact may have lead me to hear what I wanted to hear. We felt somewhat rushed to make sure we completed the trip on schedule.
Fractional Jet crew reported descending below cleared altitude on approach to LWB when erroneously believed were cleared for a visual approach.