Turkish F-16 and Russian Su-27 pilots escort a simulated renegade aircraft over the Black Sea during a joint NATO-Russian exercise called Vigilant Skies 2011 on 8 June 2011. The joint exercise, sponsored by the NATO-Russia Council Cooperative Airspace Initiative, known as NRC CAI, is designed to prevent terrorist attacks via civilian aircraft. The initiative allows officials of NATO nations and Russia to share real-time air information on movements in both NATO and Russian airspace and to coordinate the response to renegade aircraft events in the border areas, including interception. US Air Force officials from Electronic Systems Command at Hanscom AFB, Massachusetts, provided technical assistance and oversight during the exercise.
