Narrative:

The problem occurred due to the pilot of medium large transport X deviating from an assigned speed creating a loss of standard separation. Corrective action was taken by the local controller. Contributing factors were as follows: 2 additional pltdevs from control instructions. Both the pilot of medium large transport X and light transport Y failed to contact tower as instructed. The lack of clearly defined areas of responsibility for separation on final. The amount of traffic at the time of occurrence. Supplemental information from acn 194778: we had been cleared for the ILS approach to runway 24R at day and told to contact tower at the marker. A normal autoplt approach was set up. At GS intercept (2500 ft MSL), we began our descent and contacted tower. At 2000 ft MSL, just under the overcast, but still with in-flight visibility limited to about 1/2 mi, the tower controller, with real panic in his voice, told us to start an immediate right turn to heading 300 degrees and climb to 3000 ft. We lost no time in doing as we were told. We were then turned back over to approach control and were vectored for an uneventful second approach to runway 24R. When we landed, the captain called the tower and spoke to the tower supervisor via telephone. When asked the reason for giving us the aborted approach, the supervisor would only say that there was other traffic over the OM and that we were in conflict with him. This seemed an odd explanation, as we were just inside the marker when given the climb and turn. Supplemental information from acn 194788: procedures inadequate to preclude a future similar occurrence. Medium large transport X decelerated during final approach while using parallel ILS's. Medium large transport X was assigned a speed of 190 KTS and did decelerate to 98 KTS. Local control took corrective action by sending the medium large transport X jet around because he was too slow to fit in the sequence. Had the pilot of this aircraft maintained his assigned speed, none of this would've happened. Medium large transport X and light transport Y did not contact tower as instructed by final controller.

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Original NASA ASRS Text

Title: SIMULTANEOUS ILS APCHS TO RWY 24L-R AND MLG ON RWY 24R DIDN'T MAINTAIN SPD ASSIGNED TILL LOM CAUSING TWR TO GIVE MISSED APCH. LTSS.

Narrative: THE PROBLEM OCCURRED DUE TO THE PLT OF MLG X DEVIATING FROM AN ASSIGNED SPD CREATING A LOSS OF STANDARD SEPARATION. CORRECTIVE ACTION WAS TAKEN BY THE LCL CTLR. CONTRIBUTING FACTORS WERE AS FOLLOWS: 2 ADDITIONAL PLTDEVS FROM CTL INSTRUCTIONS. BOTH THE PLT OF MLG X AND LTT Y FAILED TO CONTACT TWR AS INSTRUCTED. THE LACK OF CLRLY DEFINED AREAS OF RESPONSIBILITY FOR SEPARATION ON FINAL. THE AMOUNT OF TFC AT THE TIME OF OCCURRENCE. SUPPLEMENTAL INFO FROM ACN 194778: WE HAD BEEN CLRED FOR THE ILS APCH TO RWY 24R AT DAY AND TOLD TO CONTACT TWR AT THE MARKER. A NORMAL AUTOPLT APCH WAS SET UP. AT GS INTERCEPT (2500 FT MSL), WE BEGAN OUR DSCNT AND CONTACTED TWR. AT 2000 FT MSL, JUST UNDER THE OVCST, BUT STILL WITH INFLT VISIBILITY LIMITED TO ABOUT 1/2 MI, THE TWR CTLR, WITH REAL PANIC IN HIS VOICE, TOLD US TO START AN IMMEDIATE R TURN TO HDG 300 DEGS AND CLB TO 3000 FT. WE LOST NO TIME IN DOING AS WE WERE TOLD. WE WERE THEN TURNED BACK OVER TO APCH CTL AND WERE VECTORED FOR AN UNEVENTFUL SECOND APCH TO RWY 24R. WHEN WE LANDED, THE CAPT CALLED THE TWR AND SPOKE TO THE TWR SUPVR VIA TELEPHONE. WHEN ASKED THE REASON FOR GIVING US THE ABORTED APCH, THE SUPVR WOULD ONLY SAY THAT THERE WAS OTHER TFC OVER THE OM AND THAT WE WERE IN CONFLICT WITH HIM. THIS SEEMED AN ODD EXPLANATION, AS WE WERE JUST INSIDE THE MARKER WHEN GIVEN THE CLB AND TURN. SUPPLEMENTAL INFO FROM ACN 194788: PROCS INADEQUATE TO PRECLUDE A FUTURE SIMILAR OCCURRENCE. MLG X DECELERATED DURING FINAL APCH WHILE USING PARALLEL ILS'S. MLG X WAS ASSIGNED A SPD OF 190 KTS AND DID DECELERATE TO 98 KTS. LCL CTL TOOK CORRECTIVE ACTION BY SENDING THE MLG X JET AROUND BECAUSE HE WAS TOO SLOW TO FIT IN THE SEQUENCE. HAD THE PLT OF THIS ACFT MAINTAINED HIS ASSIGNED SPD, NONE OF THIS WOULD'VE HAPPENED. MLG X AND LTT Y DID NOT CONTACT TWR AS INSTRUCTED BY FINAL CTLR.

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.