E-4

E-4 under the Air Force's Aircraft Procurement budget activity, aims to fund modifications to the E-4B fleet. The E-4B is a highly modified Boeing 747 airframe that supports the National Airborne Operations Center (NAOC) mission, providing national civilian and military leadership with a survivable communications node of the National Military Command System. The modifications listed within this program provide updates to maintain airframe flight worthiness certification and enhance operational capability while improving flight safety, reliability, and maintainability. Additionally, the program addresses Diminishing Manufacturing Sources and Material Shortages (DMSMS) issues involving primary mission equipment and airframe, as well as supports emerging modification requirements, Government travel, Advisory and Assistance Services Contract (A&ASC), Federally Funded Research and Development Contract (FFRDC) support, and equipment as required.

Furthermore, the program includes specific efforts such as the Advanced Extremely High Frequency/Presidential National Voice Conferencing (AEHF/PNVC), Low Frequency Transmit System (LFTS), and Survivable Super High Frequency (SSHF) modifications. These efforts involve installing advanced communication systems to meet existing Presidential Policy Directive requirements and ensure continued connectivity and interoperability as satellite and communications infrastructure evolves. The SSHF program will be acquired in two increments, with Increment 1 focusing on technical solutions such as system upgrades, while Increment 2 will include new modem technology and system upgrades. The program also involves associated Research Development Test and Evaluation funding to modify one prototype aircraft per increment. Overall, Program E-4 aims to ensure the E-4B fleet's readiness to support critical national security missions by addressing aging aircraft issues and enhancing communication capabilities.