B737 crew had near midair collision with SW4 in dfw class B.

Attributes
ACN	477130
Time
Date	200006
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : dfw.airport
State Reference	TX
Altitude	msl single value : 2500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d10.tracon
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : d10.tracon
Operator	common carrier : charter
Make Model Name	SA-226 TC Metro II
Operating Under FAR Part	Part 135
Flight Phase	descent : approach
Route In Use	approach : visual arrival : on vectors
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 40 flight time total : 7000 flight time type : 25
ASRS Report	477130
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : issued alert flight crew : became reoriented
Miss Distance	horizontal : 100 vertical : 100
Factors
Maintenance	contributing factor : non availability of parts contributing factor : schedule pressure
Supplementary
Problem Areas	Flight Crew Human Performance Company
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Dispatched with TCASII inoperative. Vectored to final at 4000 ft. Approach control advised previously of merlin traffic crossing underneath at 3000 ft proceeding to west complex. With runway in sight, we were cleared for a visual approach to runway 17C. At approximately 2500 ft, just outside the jiffy OM and still high on the GS we saw a merlin in a hard right turn at our 1 O'clock position approximately 100 ft below and 100 ft horizontally to us. According to ATC, he'd called runway 18R in sight but lined up on runway 17C. The runway 18R tower ATC personnel called abcd to make a hard right turn.

Original NASA ASRS Text

Title: B737 CREW HAD NMAC WITH SW4 IN DFW CLASS B.

Narrative: DISPATCHED WITH TCASII INOP. VECTORED TO FINAL AT 4000 FT. APCH CTL ADVISED PREVIOUSLY OF MERLIN TFC XING UNDERNEATH AT 3000 FT PROCEEDING TO W COMPLEX. WITH RWY IN SIGHT, WE WERE CLRED FOR A VISUAL APCH TO RWY 17C. AT APPROX 2500 FT, JUST OUTSIDE THE JIFFY OM AND STILL HIGH ON THE GS WE SAW A MERLIN IN A HARD R TURN AT OUR 1 O'CLOCK POS APPROX 100 FT BELOW AND 100 FT HORIZLY TO US. ACCORDING TO ATC, HE'D CALLED RWY 18R IN SIGHT BUT LINED UP ON RWY 17C. THE RWY 18R TWR ATC PERSONNEL CALLED ABCD TO MAKE A HARD R TURN.

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.