Narrative:

Our 4TH leg of the day. Short 20 min flight time to iah. Vectored for approach runway 27 at iah. 170 KIAS clearance. Approach control cleared us for visual approach following a B737 ('follow the B737') at 3 1/2 NM on a left base. He looked closer than that and as we flew toward the runway the B737 got to about 2 DME in front of us (on TCASII) and looked even closer. I began slowing at 8 DME to keep from getting any closer. We were handed to tower and cleared to land behind the B737 with 3 1/2 NM separation (approximately 7 DME). At 5 DME at 1700 ft MSL, tower sent us missed with 2000 ft, 130 degree left turn instructions, followed by turn left immediately. We were still in 'low bank' mode due to slow speed and just starting our turn. Handed to approach control and vectored for another visual approach. Controller stated we wre sent around because we slowed 2 DME early. I asked the first officer if we were speed restr and he said 'yes, 170 KTS to the marker (6 DME), you told me that.' I had forgotten the speed restr and was concentrating on the distance to the B737. This caused the aircraft behind us to get too close perhaps. It was a busy night and control was trying to squeeze us all in. Human performance factors: I perceived we were very close to the B737. It looked very close in the dark. This may have led to my focusing on that and forgetting about my speed. I should have coordinated with approach about the distance and our speed, but I didn't realize I had a problem with speed.

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Original NASA ASRS Text

Title: AN ACR FLC FLYING AN ATR42 INTO IAH IS INSTRUCTED TO ABANDON THEIR VISUAL APCH AFTER FAILING TO COMPLY WITH AN ATC SPD RESTR.

Narrative: OUR 4TH LEG OF THE DAY. SHORT 20 MIN FLT TIME TO IAH. VECTORED FOR APCH RWY 27 AT IAH. 170 KIAS CLRNC. APCH CTL CLRED US FOR VISUAL APCH FOLLOWING A B737 ('FOLLOW THE B737') AT 3 1/2 NM ON A L BASE. HE LOOKED CLOSER THAN THAT AND AS WE FLEW TOWARD THE RWY THE B737 GOT TO ABOUT 2 DME IN FRONT OF US (ON TCASII) AND LOOKED EVEN CLOSER. I BEGAN SLOWING AT 8 DME TO KEEP FROM GETTING ANY CLOSER. WE WERE HANDED TO TWR AND CLRED TO LAND BEHIND THE B737 WITH 3 1/2 NM SEPARATION (APPROX 7 DME). AT 5 DME AT 1700 FT MSL, TWR SENT US MISSED WITH 2000 FT, 130 DEG L TURN INSTRUCTIONS, FOLLOWED BY TURN L IMMEDIATELY. WE WERE STILL IN 'LOW BANK' MODE DUE TO SLOW SPD AND JUST STARTING OUR TURN. HANDED TO APCH CTL AND VECTORED FOR ANOTHER VISUAL APCH. CTLR STATED WE WRE SENT AROUND BECAUSE WE SLOWED 2 DME EARLY. I ASKED THE FO IF WE WERE SPD RESTR AND HE SAID 'YES, 170 KTS TO THE MARKER (6 DME), YOU TOLD ME THAT.' I HAD FORGOTTEN THE SPD RESTR AND WAS CONCENTRATING ON THE DISTANCE TO THE B737. THIS CAUSED THE ACFT BEHIND US TO GET TOO CLOSE PERHAPS. IT WAS A BUSY NIGHT AND CTL WAS TRYING TO SQUEEZE US ALL IN. HUMAN PERFORMANCE FACTORS: I PERCEIVED WE WERE VERY CLOSE TO THE B737. IT LOOKED VERY CLOSE IN THE DARK. THIS MAY HAVE LED TO MY FOCUSING ON THAT AND FORGETTING ABOUT MY SPD. I SHOULD HAVE COORDINATED WITH APCH ABOUT THE DISTANCE AND OUR SPD, BUT I DIDN'T REALIZE I HAD A PROB WITH SPD.

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.