FREQ BLOCKAGE CAUSED AN ACR LGT TO PASS THROUGH THE FINAL APCH COURSE AND COME INTO CONFLICT WITH AN ACR HVT INBOUND ON THE ILS.

Narrative

ZLA ASKED FOR A HIGHSPEED (330K) PENETRATION ON 25L PROFILE DESCENT TO ACCOMMODATE FOLLOWING TFC AND VECTORED ME ACROSS 'CIVET CORNER' PRESUMABLY FOR SAME PURPOSE. ON INTERCEPTION OF 25L LOC I WAS ASKED TO MAINTAIN 250K BELOW 10000' AND TURNED OVER TO LAX APCH. THEY IMMEDIATELY ASKED ME TO SLOW TO 180K AND CLRED ME '25L APCH AFTER FUELER'. INSIDE FUELER I WATCHED LGT Y APCH THE LOC FROM SLI VOR (AT 90 DEG TO LOC) PASS APPROX 2 MILES IN FRONT OF ME. AS HE APCHED THE LOC I HEARD 'CLICKS' ON THE FREQ (124.9). I ATTEMPTED; TWICE; TO CONTACT APCH ON 124.9 BUT THE FREQ WAS SILENT SO I IMMEDIATELY CONTACTED LAX APCH ON 124.5 AND EXPLAINED THAT I HAD LOST CONTACT WITH THE APCH CTLR ON 124.9 AND RECEIVED AN ACKNOWLEDGEMENT. WHEN LGT Y CROSSED THE LOC HE WAS STILL QUITE FAST WITH ONLY A SMALL FLAP SETTING SHOWING AND BECAUSE HE MADE NO ATTEMPT TO 'LEAD IN' I ASSUMED HE WAS AIMING FOR 24R. WE WERE IN THE CLEAR WITH HEAVY HAZE BELOW; TOPPING AT 2000'. I WATCHED LGT Y TURN IN TOWARD LAX. I WAS INSTRUCTED BY THE APCH CTLR TO FOLLOW LGT Y BUT INFORMED HIM THAT I WAS UNABLE. THE CTLR ACKNOWLEDGED AND INSTRUCTED ME TO MAINTAIN 4000'. I SAW LGT Y COMMENCE A DESCENDING LEFT TURN TOWARDS ME AND HE PASSED DIRECTLY BELOW ME APPROX 1000' LOWER AND XING RIGHT TO LEFT. AT THIS TIME I WAS ABOVE THE GLIDE SLOPE. I INFORMED THE CTLR THAT I NO LONGER HAD LGT Y IN SIGHT. I PROCEEDED TO LAX AT 4000' ON THE LOC AND WAS VECTORED FOR ANOTHER APCH. I SUGGEST THAT CLOSE IN TRANSITIONS BE DESIGNED AT LESS THAN 90 DEG INTERCEPTS SO THAT IN THE EVENT OF RADIO FAILURE WITH HIGH PERFORMANCE ACFT; AND THE LOSS OF 'LEAD-IN' VECTORS; THAT THE TFC ON PARALLEL RWY APCHS NOT BE JEOPARDIZED; NOR; AS IN THIS CASE; FOLLOWING TFC. LGT Y WAS FINALLY CONTACTED BY LAX APCH THROUGH COMMERCIAL RADIO; SHOWING INITIATIVE ON THE PART OF LGT Y CREW RADIO HANDLING. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING INFORMATION: AFTER LNDG THE REPORTER CALLED APCH CTL TO FIND WHAT HAPPENED. THE LGT THAT CROSSED THEIR PATH HAD 'STUCK MIKE' AND APCH CTL ON 124.9 WAS EFFECTIVELY OUT OF SERVICE. BY THE TIME RPTR DECIDED THAT THIS WAS TRUE; THE OTHER ACFT HAD ALREADY STARTED TO CROSS THEIR PATH AND STANDARD SEP HAD BEEN LOST. AS STATED IN THE NARRATIVE; THE CREW OF LGT DID NOT REGAIN CONTACT WITH APCH CTL UNTIL THEY WERE CONTACTED THROUGH COMMERCIAL RADIO AND ADVISED THAT THEY WERE THE ACFT WITH THE STUCK MICROPHONE. RPTR STATED THAT HE HAD SEEN THE OTHER ACFT WELL BEFORE IT CAME CLOSE AND AT NO TIME DID HE FEEL THAT ANY DANGER EXISTED.