Narrative:

I flew a mostly uneventful leg to sfo; the big sur arrival to the bridge visual for runway 28L. We set up and briefed for LNAV/VNAV approach in visual conditions. As we joined the final approach course ATC slowed us to 180 KTS and advised us of traffic for the parallel runway; a B767-300. The first officer and I had the traffic in sight and told ATC. ATC advised us to maintain visual separation with the B767 and continue our approach for runway 28L. As the B767 got closer it was apparent that we were getting uncomfortably close. We slowed further to 160 KTS to keep some distance between the B767 and ourselves. It was quite obvious that the B767 was becoming a threat. As the B767 flew through his and continued through our own approach course we were glad for the additional spacing that we had created. With the B767 well south of his and our runway approach and was probably a half mile or so to the left of our course and a mile or two ahead of us. (He really overshot his turn) ATC pointed out this obvious event and rather than have him cross in front of us again asked us to change runways and make runway 28R our new landing runway.I disengaged the autopilot as ATC was issuing this new clearance and as anticipated we encountered the B767's wake turbulence. After getting through the wake turbulence I commanded the first officer to deselect the flight directors and tune up runway 28R localizer all the while keeping a very suspicious eye on the B767 as he accepted his new runway as well. Once again the B767 seemed to slightly over shoot his course and we deviated a little bit away from him to maintain safe spacing. Approaching 1;000 ft the first officer confirmed with ATC that the B767 was really landing on 28L and that we were to land on 28R. ATC thanked us for our help and told us to continue to our landing runway; 28R. After landing (side by side with the B767) we turned off our runway and held short of runway 28L). We thanked each other for the successful event. The first officer called the tower (after switching to tower frequency) advising that we were holding short. 'Ahh [flight #]; nice to finally talk to you (sarcastically). Cross runway 28L; contact ground.' after clear of all runways I reached up to turn off my landing lights and realized that my taxi light was in the off position (technique; I know). This is what led to my suspicion that we most likely had not received proper clearance. After the parking checklist we exchanged ideas as to what just happened and what may have happened as a result. (The first officer told me of the tower frequency being in standby and approach still being active and I told him of my taxi light reminder). Our individual perspectives along with the tower controller's (non-threatening) comment led us to the conclusion that we had landed without proper clearance. We were distracted. We overcame a lot of distractions from the time that the B767 was pointed out to us until we touched down we were busy. Neither of us remembered getting handed off to the tower. We were still talking to approach coming through 1;000 ft and we likely interpreted the 'continue...landing runway 28R' as our landing clearance.

Related reports:

Google
 

Original NASA ASRS Text

Title: B737 landed in SFO without clearance after dealing with problems stemming from close spacing on the parallel runway; including wake vortex encounter.

Narrative: I flew a mostly uneventful leg to SFO; the Big Sur Arrival to the Bridge Visual for Runway 28L. We set up and briefed for LNAV/VNAV approach in visual conditions. As we joined the final approach course ATC slowed us to 180 KTS and advised us of traffic for the parallel runway; a B767-300. The First Officer and I had the traffic in sight and told ATC. ATC advised us to maintain visual separation with the B767 and continue our approach for Runway 28L. As the B767 got closer it was apparent that we were getting uncomfortably close. We slowed further to 160 KTS to keep some distance between the B767 and ourselves. It was quite obvious that the B767 was becoming a threat. As the B767 flew through his and continued through our own approach course we were glad for the additional spacing that we had created. With the B767 well south of his and our runway approach and was probably a half mile or so to the left of our course and a mile or two ahead of us. (He really overshot his turn) ATC pointed out this obvious event and rather than have him cross in front of us again asked us to change runways and make Runway 28R our new landing runway.I disengaged the autopilot as ATC was issuing this new clearance and as anticipated we encountered the B767's wake turbulence. After getting through the wake turbulence I commanded the First Officer to deselect the flight directors and tune up Runway 28R localizer all the while keeping a very suspicious eye on the B767 as he accepted his NEW runway as well. Once again the B767 seemed to slightly over shoot his course and we deviated a little bit away from him to maintain safe spacing. Approaching 1;000 FT the First Officer confirmed with ATC that the B767 was really landing on 28L and that we were to land on 28R. ATC thanked us for our help and told us to continue to our landing runway; 28R. After landing (side by side with the B767) we turned off our runway and held short of Runway 28L). We thanked each other for the successful event. The First Officer called the Tower (after switching to Tower frequency) advising that we were holding short. 'Ahh [flight #]; nice to finally talk to you (sarcastically). Cross Runway 28L; contact Ground.' After clear of all runways I reached up to turn off my landing lights and realized that my taxi light was in the OFF position (technique; I know). This is what led to my suspicion that we most likely had not received proper clearance. After the Parking Checklist we exchanged ideas as to what just happened and what may have happened as a result. (The First Officer told me of the Tower frequency being in standby and Approach still being active and I told him of my taxi light reminder). Our individual perspectives along with the Tower Controller's (non-threatening) comment led us to the conclusion that we had landed without proper clearance. We were distracted. We overcame a lot of distractions from the time that the B767 was pointed out to us until we touched down we were busy. Neither of us remembered getting handed off to the Tower. We were still talking to Approach coming through 1;000 FT and we likely interpreted the 'continue...landing Runway 28R' as our landing clearance.

Data retrieved from NASA's ASRS site as of July 2013 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.