ASRS 1693388

Reporter 1

On a flight into BTL we had briefed a visual approach to Runway 23R back up with the ILS. Upon arrival to BTL the Tower cleared us to land Runway 23R, after landing and taxiing off the runway the Tower cleared us to parking with him. It was at this point I realized we had landed on Runway 23L. No indication of the error was given by the Tower. Taxied into the ramp uneventful and shut down. Both of us had a duty day over twelve hours with connecting airline flight and an hour long car ride to reach the airplane followed by a flight to BTL. Fatigue was without a doubt a factor.

Reporter 2

Flying in to BTL we were cleared to land on Runway 23R. ATIS was telling us Runway 31 was in use and we briefed enroute we would ask for Runway 23R and we did. We approached the airport from the southeast. Tower cleared us to land and the Pilot Flying began to turn directly to the airport like he was setting up for final on Runway 31. I corrected him and told him he needs a base for Runway 23R. Pilot Flying then asked if the REILS that were flashing was the intended runway and I said yes (it matched my centerline direction) and he then turned for a base leg for Runway 23L. We landed on Runway 23L without the Tower correcting us at all. I was distracted from our approach which was short and lower than I like. We were turning on Final at 500 feet AGL and realized we were landing on Runway 23L just before touchdown. I knew it was long enough from the briefing but my centerline was for Runway 23R. I can only contribute not matching the two due to fatigue. We both had the ILS Runway 23R set in and did not catch it. I always have a centerline which has helped a handful of times over the years. After landing we asked the Tower if we should go to ground for taxi (we were clear of runway) and he said to stay with him. We did not get any taxi instructions and proceeded to [FBO]. The Tower never asked about the landing and we were not given a phone number to call anyone. I can only attribute to us both being fatigued a little bit the reason we landed on the wrong runway. We should have gone around when Pilot Flying was confused about the approach to Runway 31. If we had gone around we would've realized the error. The Tower didn't correct us but we should've landed on the right runway.