A320
Air Traffic Control Fully Certified
Communication Breakdown
ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance
Procedure
An A320 was enroute on course to KU45Q when I; the ZLC R46 Controller took the hand off from ZLA R33. The A320 made an unexpected turn right of course. I called ZDV R23 to make a point out prior to the aircraft violating ZDV's airspace. ZDV Sector 23 Controller called RADAR Contact. I then asked the A320 what fix he was navigating to when I think the pilot responded with KU45S (KU54S was the next fix in the Airbus' flight plan). I called ZDV Sector 23 and coordinated that the Airbus was direct KU54S. After talking to several controllers I discovered this has happened several times before. The two fixes KU45S and KU54S are only 100 miles apart; but are too easily mis-entered and misheard on a read back/coordination call.  When KU54S is the fix in the NAS flight plan after KU45Q; and the aircraft has KU45S entered into autopilot; the flight plan will not auto flash to ZDV Sector 23 and the controller only has 60 seconds to realize that the aircraft is off course (and that the issue is not related to 'vector wobble' ERAM discrepancies) before violating ZDV's airspace. The 'K' fix naming convention needs to be changed. It is too dangerous having two fixes with such a similar naming convention in such close proximity.
ZLC Controller described an unexpected course change by an air carrier; the reporter expressing concern regarding the similar 'K' fix naming convention as problematic.