Several ARTCC Controllers reported a loss of separation when an aircraft filed on NAVIGATION REFERENCE SYSTEM (NRS) waypoints makes an unanticipated turn.
Synopsis
Several ARTCC Controllers reported a loss of separation when an aircraft filed on NAVIGATION REFERENCE SYSTEM (NRS) waypoints makes an unanticipated turn.
Narrative
Aircraft X was northwest bound at FL360. Sector XW handed Aircraft X to me on Sector YU. I accepted the handoff because it appeared that the aircraft was headed into my sector on a normal route that we see all day. Sector XW then called to coordinate that Aircraft Y; which had already been pointed out to me; was going to climb from FL350 to FL370. Both aircraft were in XW's airspace and it appeared the Aircraft Y would pass behind the Aircraft X. However; Aircraft X was not on a normal route. A few minutes later Aircraft X turned left about 30 degrees at KZ10W [a Navigation Reference system Fix]. KZ10W; a fix in the middle of nowhere that is about a mile from actually getting into my airspace. The turn put the aircraft in conflict and although I turned the Aircraft X and Sector XW turned the Aircraft Y; there was not enough time to keep separation. The 'K' fix that Aircraft X filed; like all the 'K' fixes; is not depicted anywhere on our maps and none of the Controllers in the area at the time had ever seen an aircraft turn at that particular fix. I; nor the XW Controller; knew that there was even a fix there. So the assumption on both parties was that Aircraft X was proceeding northwest bound into my airspace; when in fact; he turn just before and never entered my airspace. Several years ago when these fixes were put in the system; this exact scenario was brought up by Controllers as an error waiting to happen. When thousands of aircraft fly through your airspace on the same route day after day; and then one turns 30 degrees nowhere near a depicted fix; it is going to catch controllers by surprise. Also; if you are going to clear an aircraft down line to one of these 'K' fixes; you do not know where it goes until you actually enter the fix and bring up a route line. You know that the fix is in Kansas City Center some where but it could be a 30 degree left turn or perhaps 30 degrees right.First depict the fixes on our radar so we know the fixes in our own airspace. Then scrap the 'K' fix grid and make a grid that makes since to people not just computer entries.
Second reporter narrative
Aircraft Y FL350 requested FL370 as I was being briefed. The R-person said he had his request and would have the climb in 2 minutes. The D-side coordinated for higher with Sector YX and said we had control. I sat down after the briefing and climbed Aircraft Y to FL370 since he was well clear of Aircraft X FL360 northwest bound handed off and communications transferred to Sector YU. A Developmental came in to train and I told him to sit down so I could brief him. I had been there maybe a minute. I began the briefing and as I was briefing I noticed Aircraft X was turning hard to the left at least 50 degrees. I told the D-side to call Sector YU and find out what was going on. I then turned the Aircraft Y 15 degrees right and got no response; I tried twice more with no response; I then called just his callsign and he answered; I then turned him 30 degrees right and he responded saying he answered every time but I could not hear him and neither could the D-side or Developmental. I figured the Sector YU Controller had turned the Aircraft X in our airspace but later found out the turn was a filed route using KZ10W then another 'K fix' which we are not familiar with. I have always said that these fixes would bite us one day and they did. That flight should have never been handed off or shipped to Sector YU since it never entered their airspace. However this was accomplished prior to the briefing and my arrival at the sector.I've still never figured out the reason for these numerous waypoints that have been established throughout the country. The majority of them are in violation of LOA's and we have to change them when we recognize the problem. Other fixes are filed through Restricted areas and we have to change these. Had I known that this flight was on one of these routes I would have changed it to something we are familiar with and in compliance with the LOA. Because I had not been there long enough to know the situation I could not fix it. But I do say that the use of these fixes is a safety hazard for us as Controllers. We are not familiar with them and there is not a map close by to get familiar with them.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.