Narrative:

On downwind lax for runway 25L visual approach cleared us to turn right base and maintain 4000 ft. They pointed out inbound 24 traffic and advised to maintain 4000 until past the runway 24 traffic. I leveled off at 4000 and passed above and behind the traffic. As a result of this 'traffic watch' the next min became very busy. Looking for traffic, lots of radio traffic, the configuring for a steep approach and turn onto 25L ILS, checklists, etc, caused our distraction. We both recall switching to tower and receiving a clearance to land 25L. After we landed we turned onto the high speed and the first officer remarked that something was not right with the frequency selector. As he had looked at the frequency selector he saw that the #1 window had ground control selected and the #2 window had approach control selected. We quickly tuned the tower frequency and we heard 'do you read us now air carrier X?' we responded and we were advised to hold between runways. Nothing else was said. So, now we were asking ourselves -- did we get clearance to land? There are, in retrospect, 4 possible scenarios: 1) we did not switch to the tower frequency, but thought that we had, and as a result did not get a clearance to land. 2) we switched back to approach thinking we were now on tower and reported in and heard approach say 'cleared to 25L' or some similar phrase that sounded like a clearance to land and landed 25L without clearance from tower thinking we had one. 3) first officer selected tower, called, received the clearance, then, in the heat of battle set ground in the window in anticipation of calling clearing runways and inadvertently placed ground control frequency in the tower window. This means we did hear a legal 'cleared to land' and then at about 500 ft left tower frequency inadvertently setting up for the confusion on the ground as to our calls. 4) in any case there is the possibility that the tower, as they frequently do, cleared us to land without waiting for our call and we did not hear them as we were on another frequency because of one of the above scenarios. Callback conversation with reporter revealed the following information: reporter gave more information reference aircraft and his flight time and ratings. Says that there was no review of incident by telephone and has been no followup by FAA. Is almost positive that approach controller did tell them to contact the tower at the OM, but unsure if first officer acknowledged. Thinks scenario #1 in his report is the most likely. Gave description of work schedule for 3 day trip and says fatigue was contributing factor.

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Original NASA ASRS Text

Title: LNDG WITHOUT CLRNC BY ACR. UNAUTHORIZED LNDG.

Narrative: ON DOWNWIND LAX FOR RWY 25L VISUAL APCH CLRED US TO TURN R BASE AND MAINTAIN 4000 FT. THEY POINTED OUT INBOUND 24 TFC AND ADVISED TO MAINTAIN 4000 UNTIL PAST THE RWY 24 TFC. I LEVELED OFF AT 4000 AND PASSED ABOVE AND BEHIND THE TFC. AS A RESULT OF THIS 'TFC WATCH' THE NEXT MIN BECAME VERY BUSY. LOOKING FOR TFC, LOTS OF RADIO TFC, THE CONFIGURING FOR A STEEP APCH AND TURN ONTO 25L ILS, CHKLISTS, ETC, CAUSED OUR DISTR. WE BOTH RECALL SWITCHING TO TWR AND RECEIVING A CLRNC TO LAND 25L. AFTER WE LANDED WE TURNED ONTO THE HIGH SPD AND THE FO REMARKED THAT SOMETHING WAS NOT RIGHT WITH THE FREQ SELECTOR. AS HE HAD LOOKED AT THE FREQ SELECTOR HE SAW THAT THE #1 WINDOW HAD GND CTL SELECTED AND THE #2 WINDOW HAD APCH CTL SELECTED. WE QUICKLY TUNED THE TWR FREQ AND WE HEARD 'DO YOU READ US NOW ACR X?' WE RESPONDED AND WE WERE ADVISED TO HOLD BTWN RWYS. NOTHING ELSE WAS SAID. SO, NOW WE WERE ASKING OURSELVES -- DID WE GET CLRNC TO LAND? THERE ARE, IN RETROSPECT, 4 POSSIBLE SCENARIOS: 1) WE DID NOT SWITCH TO THE TWR FREQ, BUT THOUGHT THAT WE HAD, AND AS A RESULT DID NOT GET A CLRNC TO LAND. 2) WE SWITCHED BACK TO APCH THINKING WE WERE NOW ON TWR AND RPTED IN AND HEARD APCH SAY 'CLRED TO 25L' OR SOME SIMILAR PHRASE THAT SOUNDED LIKE A CLRNC TO LAND AND LANDED 25L WITHOUT CLRNC FROM TWR THINKING WE HAD ONE. 3) FO SELECTED TWR, CALLED, RECEIVED THE CLRNC, THEN, IN THE HEAT OF BATTLE SET GND IN THE WINDOW IN ANTICIPATION OF CALLING CLRING RWYS AND INADVERTENTLY PLACED GND CTL FREQ IN THE TWR WINDOW. THIS MEANS WE DID HEAR A LEGAL 'CLRED TO LAND' AND THEN AT ABOUT 500 FT LEFT TWR FREQ INADVERTENTLY SETTING UP FOR THE CONFUSION ON THE GND AS TO OUR CALLS. 4) IN ANY CASE THERE IS THE POSSIBILITY THAT THE TWR, AS THEY FREQUENTLY DO, CLRED US TO LAND WITHOUT WAITING FOR OUR CALL AND WE DID NOT HEAR THEM AS WE WERE ON ANOTHER FREQ BECAUSE OF ONE OF THE ABOVE SCENARIOS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR GAVE MORE INFO REF ACFT AND HIS FLT TIME AND RATINGS. SAYS THAT THERE WAS NO REVIEW OF INCIDENT BY TELEPHONE AND HAS BEEN NO FOLLOWUP BY FAA. IS ALMOST POSITIVE THAT APCH CTLR DID TELL THEM TO CONTACT THE TWR AT THE OM, BUT UNSURE IF FO ACKNOWLEDGED. THINKS SCENARIO #1 IN HIS RPT IS THE MOST LIKELY. GAVE DESCRIPTION OF WORK SCHEDULE FOR 3 DAY TRIP AND SAYS FATIGUE WAS CONTRIBUTING FACTOR.

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.