Narrative:

Cleared for ILS 26 approach (iah) assigned 210 KTS on approach. Assigned 150 KTS and slowed immediately to 150 KTS. Noticed sep was not adequate with reference to TCAS. Sep with aircraft ahead on approach was inside of 3 mi. Slowed aircraft to final approach speed. Controller assigned right turn to 360 degree heading climb and maintain 3000' to execute go around procedure. Turn to 090 degree for downwind (assigned by ATC). Controller assigned visibility approach behind another aircraft now on final approach for runway 26 at approximately 3000'. Confirmed traffic visually at 11-12 O'clock position and referenced TCAS for aircraft position. No sequence indicated. Turned base leg and in a turn to final when controller requested that we climb 'immediately' to 400' on 180 degree heading (base leg to final). Conflict aircraft was at 11 O'clock and same altitude for runway 26, also. TCAS avoidance (RA) was executed. Another controller assigned position for vectors back to approach, with no further incident. Conclusion: speed control by ATC in air traffic area at critical moments controling multiple airliners was poor. Other aircraft in area were having similar spacing problems causing first conflict. Pilot is always responsible for his own sep once cleared for a visibility approach provided ATC has the responsibility of assigning proper identify and sequence of aircraft to follow. If any error is made by either party once an assignment is made on downwind leg as to what aircraft to follow, ATC should not wait until final approach to note the discrepancy in the pattern. 2 aircraft should never have the same altitude assignment in same proximity against traffic inbound to runway 26. TCAS should never have to be used to note sep between aircraft. Pilot vigilance should be outside the aircraft in the air traffic area.

Related reports:

Google
 

Original NASA ASRS Text

Title: LATE CLRNC AND TRAFFIC CAUSED GO AROUND.

Narrative: CLRED FOR ILS 26 APCH (IAH) ASSIGNED 210 KTS ON APCH. ASSIGNED 150 KTS AND SLOWED IMMEDIATELY TO 150 KTS. NOTICED SEP WAS NOT ADEQUATE WITH REF TO TCAS. SEP WITH ACFT AHEAD ON APCH WAS INSIDE OF 3 MI. SLOWED ACFT TO FINAL APCH SPD. CTLR ASSIGNED RIGHT TURN TO 360 DEG HDG CLB AND MAINTAIN 3000' TO EXECUTE GAR PROC. TURN TO 090 DEG FOR DOWNWIND (ASSIGNED BY ATC). CTLR ASSIGNED VIS APCH BEHIND ANOTHER ACFT NOW ON FINAL APCH FOR RWY 26 AT APPROX 3000'. CONFIRMED TFC VISUALLY AT 11-12 O'CLOCK POS AND REFERENCED TCAS FOR ACFT POS. NO SEQUENCE INDICATED. TURNED BASE LEG AND IN A TURN TO FINAL WHEN CTLR REQUESTED THAT WE CLB 'IMMEDIATELY' TO 400' ON 180 DEG HDG (BASE LEG TO FINAL). CONFLICT ACFT WAS AT 11 O'CLOCK AND SAME ALT FOR RWY 26, ALSO. TCAS AVOIDANCE (RA) WAS EXECUTED. ANOTHER CTLR ASSIGNED POS FOR VECTORS BACK TO APCH, WITH NO FURTHER INCIDENT. CONCLUSION: SPD CTL BY ATC IN ATA AT CRITICAL MOMENTS CTLING MULTIPLE AIRLINERS WAS POOR. OTHER ACFT IN AREA WERE HAVING SIMILAR SPACING PROBS CAUSING FIRST CONFLICT. PLT IS ALWAYS RESPONSIBLE FOR HIS OWN SEP ONCE CLRED FOR A VIS APCH PROVIDED ATC HAS THE RESPONSIBILITY OF ASSIGNING PROPER IDENT AND SEQUENCE OF ACFT TO FOLLOW. IF ANY ERROR IS MADE BY EITHER PARTY ONCE AN ASSIGNMENT IS MADE ON DOWNWIND LEG AS TO WHAT ACFT TO FOLLOW, ATC SHOULD NOT WAIT UNTIL FINAL APCH TO NOTE THE DISCREPANCY IN THE PATTERN. 2 ACFT SHOULD NEVER HAVE THE SAME ALT ASSIGNMENT IN SAME PROX AGAINST TFC INBND TO RWY 26. TCAS SHOULD NEVER HAVE TO BE USED TO NOTE SEP BTWN ACFT. PLT VIGILANCE SHOULD BE OUTSIDE THE ACFT IN THE ATA.

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.