While the U.S. Air Force is considering an acceleration of the E-4C Survivable Airborne Operation Center (SAOC) by Sierra Nevada Corp. (SNC) an increased buy of SAOCs beyond the four planned by the service is unlikely, Air Force Secretary Troy Meink said on Tuesday. "I don't know that we need more SAOC aircraft than we're planning on right now," Meink said at the McAleese and Associates' annual defense programs conference. "I actually don't think we do." A U.S Army Corps…