2009-12 · NASA ASRS report 863635
Enroute CIC described loss of separation event when a developmental misunderstood altitude separation requirements above FL410 applying less than the 2000 feet required.
At the time of the incident I was preforming Controller-In-Charge (CIC) duties at the watch desk. I had assigned the controller to the sector XX RADAR position; knowing that he was not yet a full CPC (Certified Professional Controller); but was qualified to work that position. There were no factors that would increase the sector difficulty (weather; military activity; equipment issues; traffic projections from metering alert...) so an assistant was not assigned to sector XX RA position. My first indication that there was any problem was when the OMIC (Operations Manager In Charge) called down with an OEDP (Operational Error Detection Program) alert. Recommendation; perhaps the new policy of letting a developmental controller work a sector alone prior to his/her 4th sector qualification may be looked at again. The controller expressed some confusion over the vertical separation requirements outside RVSM airspace; specifically at or above FL410. Perhaps a briefing of some type; encouraging developmental controllers to ask questions or request assistance if there is any doubt whatsoever about procedures or separation from the Front Line Manager (FLM)/CIC or any CPC nearby. That doing this will not make them look 'weak' or inferior but it is simply another tool insuring safety.
Aircraft X was an aircraft climbing into my sector asking for a final altitude of FL430. He was climbing very rapidly into a 120 knot head wind. With the climb from FL370 to FL430 being a large climb I spanned out my scope to scan for oncoming traffic. About fifteen minutes out I pulled up a limited data-block of a Aircraft Y at FL410. Aircraft Ywas flying with the large tail wind and was moving a lot faster than Aircraft X. I asked Aircraft X if he could be at or above FL420 in five minutes or less; thinking that in this phase of flight I only needed 1000 ft separation. I misinterpreted this rule; thinking that if the aircraft was climbing to the assigned altitude of FL430 I only needed to miss the oncoming traffic (Aircraft Y) by 1000 ft. I realize now that 2000 ft separation is needed at or above FL410; but at the time my interpretation was that I only needed 1000 ft. With this in mind I cleared Aircraft Xto FL430 with an expeditious rate through FL420. I took the hand off on Aircraft Y and place a J-ring on Aircraft Y. Aircraft X climbed well and was above FL420 with ten miles or more lateral separation to spare. At this point I thought I had ensured separation between the two aircraft. I handed off Aircraft X to sector 25; and the hand off was taken. Within a few minutes the conflict alert went off between Aircraft X and Aircraft Y; when this happened it occurred to me that I may have misinterpreted the rule. I was given a call from sector 25 releasing control to turn Aircraft X within their airspace. At this time I realized I had misinterpreted the rule and immediately took action to rectify the problem. I asked Aircraft X to be level in thirty seconds or less; I turned Aircraft Y 30 degrees right; then turned the Aircraft X 30 degrees right. I got read backs on all clearances except the 30 degree right turn to Aircraft X; I issued the 30 degree turn to the Aircraft X again with no read back once more. At this time to ensure further separation I descended Aircraft Y to FL400. Separation was lost; 1400 ft vertically and 4.25 NM laterally. I believe that if I had not misinterpreted this rule I would not have climbed the Aircraft X to FL430; I would have ensured separation by stopping Aircraft X at FL400 until lateral separation was meet. I now understand that I misinterpreted this rule and that 2000 ft separation is needed at or above FL410. Recommendation; I would reiterate the fact in training that 2000 ft separation is needed about FL410 at all times. Also a training discussion could be implemented explaining the reasons for 2000 ft separation and why FL420 cannot be used as an assignable altitude.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.
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