Zulu X-Ray 6 (ZX6) was the callsign for Vandenberg Air Force Base in California. It appears in the Call of Duty: Modern Warfare 2 level "Wolverines!". NORAD reports that they've picked up 100 bogeys in the region. Zulu X-Ray however says their scopes are clear, and suggests a problem with sun spots or solar activity. It is found out seconds later that a massive contingent of Russian aircraft are all over Washington D.C. by Sierra Delta.