Narrative:

I was working rxx/xy. I was told that we would be getting some ZZZ and ZZZ1 landers. Rxy was split several minutes later. I began to get ZZZ1 and ZZZ landers as expected. Several minutes later; I was told that I was required to get 15 miles in-trail to ZZZ1. Rxy asked the supervisor for relief on the in-trail. We were told that we need the 15 mit. Shortly after; rxz called with a point-out on an aircraft landing ZZZ1. I approved it and began to vector the two lead ZZZ1s behind the point-out. Next I began to get aircraft from rxa also landing ZZZ1 who were tied up with the ZZZ1 landers tied up with the aircraft coming from rxb; rxc; and rxz. In addition; rxy also had several ZZZ1 landers and we were attempting to sequence them and provide the required 15 mit. Furthermore; I had several ZZZ landers coming from rxb; rxc; and rxe that I was attempting to get in-trail spacing on. I would estimate I had 13-15 aircraft; most of whom were landing ZZZ1 or ZZZ and I was trying to get in-trail spacing on. A B737-800 was a ZZZ1 lander from rxa that I put on a 270 heading for sequencing. An A319 was a ZZZ lander from rxb who I turned out for spacing. I was putting the B737 behind a ZZZ1 that rxy was working. I turned the A319 back to [an intersection that was near]. As a came back around in my scan; I saw the A319 at FL310 turning back into the B737 at FL310. At that point; I would estimate the aircraft were 7 miles apart. I told the A319 to descend to FL270 and expedite the descent. I issued a traffic alert to the B737 for the A319. I then issued a traffic alert to the A319 for B737. The B737 reported the A319 in sight. A few moments later A319 reported the B737 in sight. I then asked to be relieved. When this happens several things need to occur. 1) aircraft from rxa need to be routed [to intersection1] and not given direct [intersection2]. [Intersection1] is 75 miles from the rxx/xd boundary. [Intersection1] is 10 miles. Sending aircraft direct there doesn't give the controllers sufficient time to create a plan and execute it for sequencing before going into rxf (which is directly below rxg). 2) aircraft can just be sent into xx/xy and hope they can sort it out. They should be held in rxa airspace or at least coordinated with xx to ensure that the routing is good. 3) you can't just send 15 aircraft from 5 different sectors; with no plan from tmu or management; slap in-trail on the last minute; and then hope the controller can sort it out. The decision needs to be made to slow the rate of flow in xx/xy to a level manageable by the controller at xx. Whether that comes from holding aircraft until xx is ready; slowing aircraft; to reduce the rate at which they enter xx; or routing them through rxb/xc before xx so that xb/xc can blend them and start something for xx; preferably a combination of the above. Finally; someone needs to let ZZZ2 know that what we can and can't do. 15 mit at that time wasn't realistic. Give them 5-10 on the first wave and then 15 there after.

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Original NASA ASRS Text

Title: Enroute Controller described an unsafe condition when weather factors; re-routes; workload and poor supervisory/TMU decisions led to a loss of separation.

Narrative: I was working RXX/XY. I was told that we would be getting some ZZZ and ZZZ1 landers. RXY was split several minutes later. I began to get ZZZ1 and ZZZ landers as expected. Several minutes later; I was told that I was required to get 15 miles in-trail to ZZZ1. RXY asked the Supervisor for relief on the in-trail. We were told that we need the 15 MIT. Shortly after; RXZ called with a point-out on an aircraft landing ZZZ1. I approved it and began to vector the two lead ZZZ1s behind the point-out. Next I began to get aircraft from RXA also landing ZZZ1 who were tied up with the ZZZ1 landers tied up with the aircraft coming from RXB; RXC; and RXZ. In addition; RXY also had several ZZZ1 landers and we were attempting to sequence them and provide the required 15 MIT. Furthermore; I had several ZZZ landers coming from RXB; RXC; and RXE that I was attempting to get in-trail spacing on. I would estimate I had 13-15 aircraft; most of whom were landing ZZZ1 or ZZZ and I was trying to get in-trail spacing on. A B737-800 was a ZZZ1 lander from RXA that I put on a 270 heading for sequencing. An A319 was a ZZZ lander from RXB who I turned out for spacing. I was putting the B737 behind a ZZZ1 that RXY was working. I turned the A319 back to [an intersection that was near]. As a came back around in my scan; I saw the A319 at FL310 turning back into the B737 at FL310. At that point; I would estimate the aircraft were 7 miles apart. I told the A319 to descend to FL270 and expedite the descent. I issued a traffic alert to the B737 for the A319. I then issued a traffic alert to the A319 for B737. The B737 reported the A319 in sight. A few moments later A319 reported the B737 in sight. I then asked to be relieved. When this happens several things need to occur. 1) Aircraft from RXA need to be routed [to intersection1] and not given direct [intersection2]. [Intersection1] is 75 miles from the RXX/XD boundary. [Intersection1] is 10 miles. Sending aircraft direct there doesn't give the controllers sufficient time to create a plan and execute it for sequencing before going into RXF (which is directly below RXG). 2) Aircraft can just be sent into XX/XY and hope they can sort it out. They should be held in RXA airspace or at least coordinated with XX to ensure that the routing is good. 3) You can't just send 15 aircraft from 5 different sectors; with no plan from TMU or management; slap in-trail on the last minute; and then hope the controller can sort it out. The decision needs to be made to slow the rate of flow in XX/XY to a level manageable by the controller at XX. Whether that comes from holding aircraft until XX is ready; slowing aircraft; to reduce the rate at which they enter XX; or routing them through RXB/XC before XX so that XB/XC can blend them and start something for XX; preferably a combination of the above. Finally; someone needs to let ZZZ2 know that what we can and can't do. 15 MIT at that time wasn't realistic. Give them 5-10 on the first wave and then 15 there after.

Data retrieved from NASA's ASRS site as of July 2013 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.