Narrative:

I was heading to pocatello airport. 15 miles east of pocatello I listen to ATIS and got mike. I didn't know I had the wrong tower frequency on which was 118.5 for idaho falls instead of pocatello tower 119.1. So I called up and said good morning pocatello tower aircraft X. Tower replied pocatello tower aircraft X go ahead. I reported aircraft X is 13 miles east of pocatello 8500 feet we have information mike for runway 21. Tower replied report 5 miles left base 21. At no point here I thought something is wrong. I reported 5 miles left base 21 and was cleared to land. I landed shortly after runway 21. No other traffic was in vicinity of airport. I called up ground didn't reply. I later pulled up and parked at FBO and got a call in building about landing and entering delta airspace without clearance. I was shocked and told tower it doesn't make sense I was talking to him 13 miles out and had cleared me to land. We later realized I was talking to idaho falls tower and at no point did idaho falls tower realize that. First thing I told pocatello tower I never mentioned even once idaho falls and nor did idaho falls tower tell me he was idaho falls. Secondly I reported mike for ATIS which at that particular time idaho falls had different information for ATIS. Thirdly I was 13 miles east of pocatello if indeed I was going to idaho falls if tower assumed that I was about 25 miles west of idaho falls and the clearance would've been report left downwind 21 not left base for 21.

Google
 

Original NASA ASRS Text

Title: Small Transport pilot reported landing without a clearance from the proper controlling facility.

Narrative: I was heading to Pocatello airport. 15 miles east of Pocatello I listen to ATIS and got Mike. I didn't know I had the wrong tower frequency on which was 118.5 for Idaho Falls instead of Pocatello tower 119.1. So I called up and said good morning Pocatello Tower Aircraft X. Tower replied Pocatello tower Aircraft X go ahead. I reported Aircraft X is 13 miles east of Pocatello 8500 feet we have information Mike for Runway 21. Tower replied report 5 miles left base 21. At no point here I thought something is wrong. I reported 5 miles left base 21 and was cleared to land. I landed shortly after Runway 21. No other traffic was in vicinity of airport. I called up Ground didn't reply. I later pulled up and parked at FBO and got a call in building about landing and entering Delta airspace without clearance. I was shocked and told Tower it doesn't make sense I was talking to him 13 miles out and had cleared me to land. We later realized I was talking to Idaho Falls Tower and at no point did Idaho Falls Tower realize that. First thing I told Pocatello Tower I never mentioned even once Idaho Falls and nor did Idaho Falls Tower tell me he was Idaho Falls. Secondly I reported Mike for ATIS which at that particular time Idaho Falls had different information for ATIS. Thirdly I was 13 miles east of Pocatello if indeed I was going to Idaho Falls if Tower assumed that I was about 25 miles west of Idaho Falls and the clearance would've been report left downwind 21 not left base for 21.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.