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.