The U.S. Air Force has launched a new acquisition program to replace four Boeing E-4B aircraft with the Survivable Airborne Operations Center (SAOC) weapon system. 
An industry day will be held at Hanscom AFB, Massachusetts, in February to brief industry on details of the acquisition strategy for the SAOC program, the Air Force Life Cycle Management Center’s Battle Management office says in a Dec. 4 notice. 
The only detail released so far about the SAOC is that it should be a derivative of a commercial aircraft, according to the notice. Likewise, the E-4B is derived from the Boeing 747-200. 
First delivered to the Air Force in 1974 as the E-4A, the fleet allows the president and the Joint Chiefs to respond to a nuclear attack even if a pre-emptive first strike has destroyed the military’s underground command centers. 
The Air Force has been studying replacement options for the E-4B fleet for more than a year. In August 2018, the Air Force sought industry feedback on a concept to replace three fleets of commercial derivative aircraft, including the E-4B, with a common airframe.