 In March 1996, the USAF activated the 513th Air Control Group (513 ACG), an ACC-gained Air Force Reserve Command (AFRC) AWACS unit under the Reserve Associate Program.Collocated with the 552 ACW at Tinker AFB, the 513 ACG which performs similar duties on active duty E-3 aircraft shared with the 552 ACW.The USAF has a total of thirty-one E-3s in active service.