|Appears in||Call of Duty: Modern Warfare 2 (Mentioned only)|
- "They're everywhere!"
- — Sierra Delta's reaction when seeing the Russian invaders.
Sierra Delta was the early warning station for the Washington, D.C. area in the level "Wolverines!" in Call of Duty: Modern Warfare 2. Sierra Delta is the callsign for the Air Traffic Control, as seen when subtitles are turned on.
Call of Duty: Modern Warfare 2Edit
The North American Aerospace Defense Command (NORAD) was checking on stations about seeing "bogeys" (brevity code for unidentified aircraft) entering U.S airspace, but the station responded that their scopes were clear. When NORAD checked on Sierra Delta, the Air Traffic Controller reported fighter jets over highway I-95, the main East-Coast highway (an important strategic asset).
Only Sierra Delta had been engaged. The Russians cracked the ACS module from the fallen satellite in Kazakhstan and were able to hack into the U.S. radar systems. With this technology, they fabricated a massive attack on the West Coast while actually attacking from the East.