Traffic conflict in the dfw class B airspace resolve by a TCASII alert and a new clearance from ATC.

Attributes
ACN	541202
Time
Date	200203
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : siler
State Reference	TX
Altitude	msl single value : 11000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : d10.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival star : ukw 7
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : d10.tracon
Make Model Name	Otter DHC-3
Operating Under FAR Part	Part 135
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	541202
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : airborne less severe non adherence : published procedure
Independent Detector	aircraft equipment : tcas other controllerb other flight crewa
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Miss Distance	horizontal : 6000 vertical : 500
Supplementary
Problem Areas	ATC Human Performance Airspace Structure Flight Crew Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Approaching siler at 11000 ft on a 090 degree heading, we received a traffic alert at 2 O'clock position, 400 ft below us, climbing to our altitude. We had our TCASII on the 5 mi range and we estimate the traffic was inside 2 mi. ATC gave us a climbing right turn to immediately climb to 12000 ft. We spotted the traffic and made a climbing left turn to 12700 ft. The other aircraft (a twin otter we believe) spotted us and made a left turn. He passed behind us and ATC cleared us back to 11000 ft. I estimate that this aircraft was less than 1 mi away and 500 ft below us. I think the twin otter was in the area carrying skydivers.

Original NASA ASRS Text

Title: TFC CONFLICT IN THE DFW CLASS B AIRSPACE RESOLVE BY A TCASII ALERT AND A NEW CLRNC FROM ATC.

Narrative: APCHING SILER AT 11000 FT ON A 090 DEG HDG, WE RECEIVED A TFC ALERT AT 2 O'CLOCK POS, 400 FT BELOW US, CLBING TO OUR ALT. WE HAD OUR TCASII ON THE 5 MI RANGE AND WE ESTIMATE THE TFC WAS INSIDE 2 MI. ATC GAVE US A CLBING R TURN TO IMMEDIATELY CLB TO 12000 FT. WE SPOTTED THE TFC AND MADE A CLBING L TURN TO 12700 FT. THE OTHER ACFT (A TWIN OTTER WE BELIEVE) SPOTTED US AND MADE A L TURN. HE PASSED BEHIND US AND ATC CLRED US BACK TO 11000 FT. I ESTIMATE THAT THIS ACFT WAS LESS THAN 1 MI AWAY AND 500 FT BELOW US. I THINK THE TWIN OTTER WAS IN THE AREA CARRYING SKYDIVERS.

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.