Narrative:

Handed off to baltimore approach on frequency 119.7. Baltimore approach cleared us for visual approach to runway 15L. Advised us we were #2 following small single engine cessna to airport who was on final approach. Approach control frequency 119.7 was very busy. As we searched for small aircraft on final among city lights, saw aircraft land. We continued our approach to landing without getting permission from tower to land. I do not believe approach handed us off to tower frequency 119.4. I knew baltimore tower frequency was 119.4, and at a quick glance may have mistaken 119.7 for 119.4, and thought tower had cleared us to land on runway 15L, remembering the visual approach clearance for runway 15L. Both the PF and myself never realized we had made the landing mistake until ground control told us the tower never cleared us to land on runway 15L. It seems we were still on approach control frequency 119.7. I feel the two closely numbered frequencys caused a confusion along with the busy approach control frequency (119.7). Approach forgot about us also, by not handing us off to baltimore tower, 119.4. We did phone the tower after parking the aircraft to discuss the situation and made our apologies. Supplemental information from acn 466593: we were having trouble maintaining visual contact with traffic due to background lighting (ground lights). Having had a couple of TA's on the TCASII, we were concentrating on spacing with that traffic. We do not use this airport frequently so unfamiliar surroundings, night, and spacing of aircraft ahead were contributing factors.

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Original NASA ASRS Text

Title: LNDG WITHOUT CLRNC AT BWI, MD.

Narrative: HANDED OFF TO BALTIMORE APCH ON FREQ 119.7. BALTIMORE APCH CLRED US FOR VISUAL APCH TO RWY 15L. ADVISED US WE WERE #2 FOLLOWING SMALL SINGLE ENG CESSNA TO ARPT WHO WAS ON FINAL APCH. APCH CTL FREQ 119.7 WAS VERY BUSY. AS WE SEARCHED FOR SMALL ACFT ON FINAL AMONG CITY LIGHTS, SAW ACFT LAND. WE CONTINUED OUR APCH TO LNDG WITHOUT GETTING PERMISSION FROM TWR TO LAND. I DO NOT BELIEVE APCH HANDED US OFF TO TWR FREQ 119.4. I KNEW BALTIMORE TWR FREQ WAS 119.4, AND AT A QUICK GLANCE MAY HAVE MISTAKEN 119.7 FOR 119.4, AND THOUGHT TWR HAD CLRED US TO LAND ON RWY 15L, REMEMBERING THE VISUAL APCH CLRNC FOR RWY 15L. BOTH THE PF AND MYSELF NEVER REALIZED WE HAD MADE THE LNDG MISTAKE UNTIL GND CTL TOLD US THE TWR NEVER CLRED US TO LAND ON RWY 15L. IT SEEMS WE WERE STILL ON APCH CTL FREQ 119.7. I FEEL THE TWO CLOSELY NUMBERED FREQS CAUSED A CONFUSION ALONG WITH THE BUSY APCH CTL FREQ (119.7). APCH FORGOT ABOUT US ALSO, BY NOT HANDING US OFF TO BALTIMORE TWR, 119.4. WE DID PHONE THE TWR AFTER PARKING THE ACFT TO DISCUSS THE SIT AND MADE OUR APOLOGIES. SUPPLEMENTAL INFO FROM ACN 466593: WE WERE HAVING TROUBLE MAINTAINING VISUAL CONTACT WITH TFC DUE TO BACKGROUND LIGHTING (GND LIGHTS). HAVING HAD A COUPLE OF TA'S ON THE TCASII, WE WERE CONCENTRATING ON SPACING WITH THAT TFC. WE DO NOT USE THIS ARPT FREQUENTLY SO UNFAMILIAR SURROUNDINGS, NIGHT, AND SPACING OF ACFT AHEAD WERE CONTRIBUTING FACTORS.

Data retrieved from NASA's ASRS site as of July 2007 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.