The 551st Special Operations Squadron (551 SOS) is a squadron of the United States Air Force. It is assigned to the Air Force Special Operations Air Warfare Center and based out of Cannon AFB, New Mexico. The 551st had previously been based at Kirtland Air Force Base from 15 March 1976 until its inactivation on 10 May 2007.It was reactivated in 2009 and currently is assigned to the AFSOC and trains aircrews on the MC-130 and AC-130.