Date: 201402
Local time of day: 1801-2400
Location: D10.TRACON, TX
Flight conditions: VMC
Light: Daylight
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class B DFW
ATC / advisory: TRACON D10
Second aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Reporter organization: Government
Human factors: Workload; Situational Awareness; Communication Breakdown; Time Pressure
Second reporter function: First Officer; Pilot Not Flying
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft RA; Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Contributing factors: Airspace Structure; Procedure
Primary problem: Airspace Structure

Narrative: I was working the feeder east position. I had literally just took over the position about a minute or two ago. Before leaving the other controller had issue traffic to an A319 on a VFR that had been operating with the Departure position level at 11;600 (C182). The A319 had been level at 11;000 FT on the arrival. These aircraft were separated by 500-700 FT. This aircraft was showing 11;600 FT. I made a few transmissions to other aircraft when the A319 said he was descending due to an RA with the VFR aircraft. At this time there was a departure at his 2 o'clock 2 miles level at 10;000 FT. I issued traffic and told him he was at 10;000 FT. The A319 descended to approximately 10;600 FT before returning to his altitude later. I do not know if traffic was issued to the other aircraft involved (I was only talking to the A319. The pilot reported that this was a dangerous situation and that the other aircraft should not have been allowed to be operating right over the main arrival path like that. I advised the supervisor of the pilots' comments and he said that there was nothing we could do because the C182 was outside of the class bravo. Expand the Bravo 1;000 FT above the arrival routes (IE. the top would be 12;000 FT if the arrivals were at 11;000 FT.) This would give control to the FAA to approve or disapprove an operation such as this over a busy arrival route.


Second narrative: We immediately searched for the traffic and had it in sight (Civilian single-engine 500 feet above us) when we then got the TCAS RA to descend. The Captain turned off the autopilot and smoothly descended and complied with the RA. We notified ATC and once the traffic was clear the Captain climbed back up to our assigned altitude of 11;000 FT. During the descent ATC advised us of MD-80 1;000 FT below us. We acknowledged we had the MD-80 in sight was climbing back up to 11;000 FT. We only descended to 10;700 FT before climbing back up to altitude. We continued on the arrival and landed without incident.


Synopsis: An A319 on the DFW BYP6 Arrival at 11;000 FT in Class B took evasive action following a TCAS RA DESCEND from a single engine aircraft at 11;500 FT outside of Class B and during the descent came with 700 FT of an another Air Carrier below him also in Class B.