Local controller described a pilot declared near midair collision when the TRACON failed to establis...

Narrative:

I was taking local 1 and was in a relief briefing when the prior coordination was not correct. A B737 was on a 7 mile final going 190 KTS and an MD80 was one half mile in trail going 250 KTS. Final coordinated with local 1 to put the B737 on runway 25R. When I took the position; and the B737 checked in for runway 25L; I asked the pilot to verify they were for the left and not the right side. The B737 said they were for runway 25L. I asked the previous controller and they said; the MD80 was for the right. The MD80 [was] still on final frequency was vectored to the south then back to the north directly over top of the B737 by 400 ft estimated. The B737 said they had an RA; I issued the traffic again for the second time and verified the B737 still wanted to land. Final said the B737 was suppose to be on runway 25R but it would have been worst in my opinion if they were since the aircraft has to slow down to sidestep runways. The MD80 should have been broke out from the beginning. Also; TRACON normally calls and asks if they can put someone on the right and not the other way around. I feel this might have confused the control. If the first guy is too slow then you shouldn't slow them down more by sidestepping them. I recommend that assist one be open during traffic hours for coordinating reasons. Training was in progress on final and the trainer should have maybe stepped in earlier.

Original NASA ASRS Text

Title: Local Controller described a pilot declared NMAC when the TRACON failed to establish appropriate speed assignments causing an overtake situation between two arrival aircraft.

Narrative: I was taking Local 1 and was in a relief briefing when the prior coordination was not correct. A B737 was on a 7 mile final going 190 KTS and an MD80 was one half mile in trail going 250 KTS. Final coordinated with Local 1 to put the B737 on Runway 25R. When I took the position; and the B737 checked in for Runway 25L; I asked the pilot to verify they were for the left and not the right side. The B737 said they were for Runway 25L. I asked the previous Controller and they said; The MD80 was for the right. The MD80 [was] still on Final frequency was vectored to the south then back to the north directly over top of the B737 by 400 FT estimated. The B737 said they had an RA; I issued the traffic again for the second time and verified the B737 still wanted to land. Final said the B737 was suppose to be on Runway 25R but it would have been worst in my opinion if they were since the aircraft has to slow down to sidestep runways. The MD80 should have been broke out from the beginning. Also; TRACON normally calls and asks if they can put someone on the right and not the other way around. I feel this might have confused the control. If the first guy is too slow then you shouldn't slow them down more by sidestepping them. I recommend that assist one be open during traffic hours for coordinating reasons. Training was in progress on Final and the trainer should have maybe stepped in earlier.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1106901
Time
Date	201308
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Visual Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Local
Qualification	Air Traffic Control Fully Certified
Person 2
Function	First Officer
Experience	Flight Crew Last 90 Days 360
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Procedural Published Material / Policy

Local controller described a pilot declared near midair collision when the TRACON failed to establish appropriate speed assignments causing an overtake situation between two arrival aircraft.