Large Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1.2
Training / Qualification
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Took Evasive Action
Aircraft; Procedure
I was working two sectors combined and I became very busy.  There was a plane inbound at 110 and I gave Aircraft X a vector to pass behind this aircraft.  The assigned heading issued was 230 and climb and maintain 170.  Once the aircraft passed behind this aircraft; it needed to be turned westbound due to its route and another aircraft inbound from the south about 20 miles out at 110.  This is about the time that I became very busy.  I noticed that the two aircraft where at the same altitude on converging courses when they where about seven miles apart. I was not talking to Aircraft Y.  Issued a traffic alert and Aircraft X did not respond.  The instructions where for Aircraft X to immediately turn right heading 310 this would allow the airplanes to have diverging courses.  Aircraft X did not respond I reissued to traffic alert; still no response.  I then called the other Controller and advised of the situation.  Aircraft Y climbed to 117 and Aircraft X descended to 105. This resulting in a loss of 1.81 miles and 800 feet. Aircraft X finally responded and said he had Aircraft Y in-sight. I continued to work the position for another 20-25 minutes and Management was already aware of the situation. Once I got relieved I went to see the OM and he provided me with the distance of loss.  I then was sent to another position to relieve another controller who was needed for something else.I made a rookie mistake I should have never given up my altitude until all conflicts were resolved. This should always be the rule no matter how busy you are.  As noted above; out of no where I became very busy.  I should have kept to the basics.
Operating Aircraft Y from XXX to YYY. On Arrival 6 to 7 miles from [named] intersection level at 11;000. Received a TCAS RA Climb command indicating at least 2;000 feet per minute (may have been closer to 3;000). Captain/pilot flying took evasive action.  As I looked for traffic outside we crossed directly above Aircraft X at somewhere between 500 to 1;000 feet.  The TCAS without a doubt saved us from a mid-air collision. We received no prior warning from ATC or no TCAS TA before RA. Flight continued normally after evasive action was taken.  Moments before the RA command was given we noticed a red traffic indication on our display slightly behind us. Then right before the RA Command the traffic jumped to in front of us on the display.  I am fairly certain this was the first time any potential conflict was displayed on the screen; almost like the TCAS display was not functioning correctly although there were other targets being displayed on the screen. An alert from ATC would have been very helpful.  Usually they announce traffic that will be crossing in close proximity on the arrival/departure.  One thing that also crossed my mind was TCAS MEL's.  I recently flew an aircraft with the TCAS deferred.  Had we been in that aircraft during this incident; I likely wouldn't be here to write this report.  I think MEL's allowing flight without TCAS should be seriously reconsidered.
Controller reports of a situation where he became busy and couldn't turn an aircraft at a specific point and ends up losing separation.  Pilot reports of TCAS saving his life.