Narrative:

The sector was very busy. I was very busy with an medium large transport wbound on V276 at FL200, from rbv to intercept J228 swbound. I thought he was at FL220. A heavy transport was southbound on J228 climbing to FL200. Then I noticed they were both at FL200. The C/a did not go off, even though they were on a possible collision course, with both data blocks showing the correct altitudes. I turned medium large transport right heading 320 degrees and climbed heavy transport to FL210. Descended medium large transport to FL190. The altitudes were used because after putting the halo on heavy transport, it became apparent radar sep would be insufficient. Contributing to my thinking that medium large transport was at FL220 is that normally he is at that altitude. But there was training going on at the sector he was coming from and the trnee thought it would be helping me out to descend the aircraft to FL200, which is the altitude I hand the aircraft off to the next sector at. Aside from sheer vol, another distraction was an light transport climbing out whose mode C was xxxxing out. Shortly after sep was lost, vol was so heavy with clrncs being stepped on that I requested all aircraft on the frequency not to initiate any xmissions. In looking back, the sector was probably too busy and traffic should have been stopped. As a suggestion to prevent this particular situation from happening again, I suggest that all iad traffic, coming wbound from sector 55, be FL210 unless otherwise coordinated. FL210 is wrong altitude for direction of flight, but all of sector 39's traffic is also wbound and either climbing to even altitudes or to altitudes above our sector. Specifically, reference the iad traffic climbing southbound on J220 (metropolitan area departures). They climb to a maximum of FL200, unless meteorological conditions sometimes force them higher (a rare occurrence). This would allow the rbv-iad traffic to safely enter sector 39's airspace with altitude sep. The problem with these rbv-iad aircraft is that they almost always have to be fit in with other iad traffic. If for some reason we lost communications with aircraft at FL210, J228 on its way to iad (and in fact the rest of the route to iad) there is no opp direction traffic that might be a factor. This would also not affect sector 55's operation, as all of their traffic is also swbound, and therefore either climbing or descending to even altitudes such as dca traffic descending to FL220.

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Original NASA ASRS Text

Title: CTLR FAILED TO NOTICE 2 ACFT ON CONVERGING COURSES AT THE SAME ALT. LESS THAN STANDARD SEPARATION OCCURRED.

Narrative: THE SECTOR WAS VERY BUSY. I WAS VERY BUSY WITH AN MLG WBOUND ON V276 AT FL200, FROM RBV TO INTERCEPT J228 SWBOUND. I THOUGHT HE WAS AT FL220. A HVT WAS SBND ON J228 CLBING TO FL200. THEN I NOTICED THEY WERE BOTH AT FL200. THE C/A DID NOT GO OFF, EVEN THOUGH THEY WERE ON A POSSIBLE COLLISION COURSE, WITH BOTH DATA BLOCKS SHOWING THE CORRECT ALTS. I TURNED MLG RIGHT HDG 320 DEGS AND CLBED HVT TO FL210. DSNDED MLG TO FL190. THE ALTS WERE USED BECAUSE AFTER PUTTING THE HALO ON HVT, IT BECAME APPARENT RADAR SEP WOULD BE INSUFFICIENT. CONTRIBUTING TO MY THINKING THAT MLG WAS AT FL220 IS THAT NORMALLY HE IS AT THAT ALT. BUT THERE WAS TRNING GOING ON AT THE SECTOR HE WAS COMING FROM AND THE TRNEE THOUGHT IT WOULD BE HELPING ME OUT TO DSND THE ACFT TO FL200, WHICH IS THE ALT I HAND THE ACFT OFF TO THE NEXT SECTOR AT. ASIDE FROM SHEER VOL, ANOTHER DISTR WAS AN LTT CLBING OUT WHOSE MODE C WAS XXXXING OUT. SHORTLY AFTER SEP WAS LOST, VOL WAS SO HEAVY WITH CLRNCS BEING STEPPED ON THAT I REQUESTED ALL ACFT ON THE FREQ NOT TO INITIATE ANY XMISSIONS. IN LOOKING BACK, THE SECTOR WAS PROBABLY TOO BUSY AND TFC SHOULD HAVE BEEN STOPPED. AS A SUGGESTION TO PREVENT THIS PARTICULAR SITUATION FROM HAPPENING AGAIN, I SUGGEST THAT ALL IAD TFC, COMING WBOUND FROM SECTOR 55, BE FL210 UNLESS OTHERWISE COORDINATED. FL210 IS WRONG ALT FOR DIRECTION OF FLT, BUT ALL OF SECTOR 39'S TFC IS ALSO WBOUND AND EITHER CLBING TO EVEN ALTS OR TO ALTS ABOVE OUR SECTOR. SPECIFICALLY, REF THE IAD TFC CLBING SBND ON J220 (METRO AREA DEPS). THEY CLB TO A MAX OF FL200, UNLESS METEOROLOGICAL CONDITIONS SOMETIMES FORCE THEM HIGHER (A RARE OCCURRENCE). THIS WOULD ALLOW THE RBV-IAD TFC TO SAFELY ENTER SECTOR 39'S AIRSPACE WITH ALT SEP. THE PROB WITH THESE RBV-IAD ACFT IS THAT THEY ALMOST ALWAYS HAVE TO BE FIT IN WITH OTHER IAD TFC. IF FOR SOME REASON WE LOST COMS WITH ACFT AT FL210, J228 ON ITS WAY TO IAD (AND IN FACT THE REST OF THE ROUTE TO IAD) THERE IS NO OPP DIRECTION TFC THAT MIGHT BE A FACTOR. THIS WOULD ALSO NOT AFFECT SECTOR 55'S OPERATION, AS ALL OF THEIR TFC IS ALSO SWBOUND, AND THEREFORE EITHER CLBING OR DSNDING TO EVEN ALTS SUCH AS DCA TFC DSNDING TO FL220.

Data retrieved from NASA's ASRS site as of August 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.