Date: 201207
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Aircraft: Bombardier/Canadair Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Second aircraft: A320
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I was working Sector X. The sector was impacted by a small area of weather that caused several aircraft to deviate from there flight planned routes. In addition I was also vectoring for a twenty mile restriction to a Class B airport and had a Class C lander on a parallel course to the departures that were climbing. Also; there were additional overflight aircraft. My full attention was on the sector and the various situations I was working through. I noticed a CRJ to the north of my sector and coordinated a more direct route with Sector Y (which [required] a hard right turn). It was important that the CRJ climb to their requested altitude of FL330 so I also requested that Sector Y climb the aircraft to FL330 before transferring communication. About this time another CPC plugged in to relieve me as I was going home. We started the briefing as I continued to tweak the various situations I had to resolve. The CRJ checked on my frequency out of approximately FL248 climbing to FL330. About a minute later an A320 checks on out of approximately FL220 for FL230. It was obvious that once the CRJ completed their turn that the A320 would be a problem. I estimated I had three minutes before these two flights would cross. I climbed the A320 to FL270; mistake number one. I had looked at the CRJ's rate of climb and calculated they would be out of FL280 or even higher in three minutes; so I lead the situation believing I would have vertical. When the A320 checked on they must have been leveling off already; there rate of climb appeared normal. That was mistake number two they had been climbing faster than normal. The briefing continued and I noticed that the CRJ's rate of climb was lower than I anticipated. I asked the relieving controller if he would like me to stop the A320 at FL260; he said no. I in no way want that sentence to place blame on the relieving controller; just the facts. I am totally to blame for this miscalculation and misapplication of a rule. The briefing and worked continued. I asked the CRJ to expedite their climb out of FL280. At that time the aircraft was out of FL272. I called traffic to the A320 at about ten miles; when the A320 was out of FL 250 and told them to expect higher when traffic was clear. Mistake number three; not issuing the A320 FL260. The A320 was climbing very fast and for some reason I thought the CRJ; being out of FL272 would make it to FL280. I have to admit I actually thought that the CRJ being out of FL272 gave me a rule to use. Mistake number four. I know you can't use that rule when there are such big differences in aircraft performance. I am not sure of the exact numbers but I believe that the CRJ was out of FL278 when the A320 was at FL270. This was a total failure of myself to safeguard my sector during a more complex time and during a relief briefing. I should have issued the A320 FL240 and stepped them up from there; plain and simple. Also; I failed to recognize and compute the rate of climb of two aircraft correctly. Why didn't I just ask them their actual rates of climb. I had plenty of time to stop the A320 at FL250 and even FL260. Why didn't I just stop them. Also; I should have issued the expedite climb to CRJ a lot earlier. How about a time to climb clearance and a time check? And finally; I should have delayed the briefing by asking the relieving controller to sit on the D-side for a couple of minutes while I worked out these situations. It would have only taken a couple of minutes to resolve all issues in the sector and then I could have provided the best briefing possible.




Synopsis: Enroute Controller described an unsafe event when failing to safeguard the sector during a complex traffic period and position relief period.