An air carrier crew on vectors to dfw runway 17C and descending to 5;000 ft followed a TCAS RA from ...

Attributes
ACN	1292446
Time
Date	201509
Local Time Of Day	1201-1800
Place
Locale Reference	DFW.Airport
State Reference	TX
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Widebody Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Total 21000
Events
Anomaly	ATC Issue All Types Conflict NMAC Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Deviation - Speed All Types
Miss Distance	Horizontal 499 Vertical 499

Narrative:

We were on vectors with approach control over the vicinity of frisco or the colony; kind of on a long extended base leg; for an expected ILS to 17C. Frequency 127.05. We were given clearance to descend to 5000 ft. In the descent; at roughly 6500 ft; perhaps; we got a TA and the yellow traffic indicator at 12 o'clock. We could not spot the traffic initially. At about 6000 ft still in the descent; we got the RA and the red traffic indicator at 12 o'clock; plus new flight path guidance to climb. At that point; the relief pilot identified the traffic straight ahead and said it looked to be an experimental airplane. I disconnected the automation and hand flew the airplane in accordance with the RA instructions; which directed a climb. I smoothly climbed straight ahead to about 6500 ft or 7000 ft; roughly; the captain (pilot monitoring) notified ATC of the RA; and I returned to the original altitude and airspeed once we were clear of conflict. On the ground; at the gate; the captain planned to notify dispatch. I believe we came within 500 ft of the traffic; or possibly closer; which I think was at 5500 ft at the time.when we reported the RA to the ATC controller; she said in response that she has that traffic on TCAS; or on her radar; or something to that effect. My thought was; 'then why were we on vectors descending into it?'

Original NASA ASRS Text

Title: An air carrier crew on vectors to DFW Runway 17C and descending to 5;000 ft followed a TCAS RA from an aircraft at 5;500 ft. The aircraft was in Class B; known to ATC but not reported to the pilots prior to the TCAS alert.

Narrative: We were on vectors with Approach Control over the vicinity of Frisco or The Colony; kind of on a long extended base leg; for an expected ILS to 17C. Frequency 127.05. We were given clearance to descend to 5000 ft. In the descent; at roughly 6500 ft; perhaps; we got a TA and the yellow traffic indicator at 12 o'clock. We could not spot the traffic initially. At about 6000 ft still in the descent; we got the RA and the red traffic indicator at 12 o'clock; plus new flight path guidance to climb. At that point; the Relief Pilot identified the traffic straight ahead and said it looked to be an experimental airplane. I disconnected the automation and hand flew the airplane in accordance with the RA instructions; which directed a climb. I smoothly climbed straight ahead to about 6500 ft or 7000 ft; roughly; the Captain (pilot monitoring) notified ATC of the RA; and I returned to the original altitude and airspeed once we were Clear of Conflict. On the ground; at the gate; the captain planned to notify Dispatch. I believe we came within 500 ft of the traffic; or possibly closer; which I think was at 5500 ft at the time.When we reported the RA to the ATC Controller; she said in response that she has that traffic on TCAS; or on her radar; or something to that effect. My thought was; 'Then why were we on vectors descending into it?'

Data retrieved from NASA's ASRS site 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.

An air carrier crew on vectors to dfw runway 17C and descending to 5;000 ft followed a TCAS RA from an aircraft at 5;500 ft. The aircraft was in class B; known to ATC but not reported to the pilots prior to the TCAS alert.