The E-4B is a highly survivable flying C3 center enabling national leaders to direct nuclear and conventional forces, execute emergency war orders, and coordinate civil response actions in support of the National Military Command System (NMCS). The early E-4A first flew on June 13, 1973, reaching IOC in December 1974. The fleet was fully upgraded to E-4B standards in 1985.
It is hardened against the effects of nuclear detonations, including electromagnetic pulse (EMP). Comms and data processing capabilities include EHF Milstar SATCOM, six-channel International Maritime Satellite, and a tri-band radome that houses the SHF communications antenna. All aircraft underwent Block 1 upgrades, enhancing electronic and communications infrastructure with commercial off-the-shelf (COTS) systems.
Ongoing upgrades include replacing Milstar data links with AEHF- compatible FAB-T and modernized presidential voice-conferencing, replacing the VLF/LF transmitter and legacy SHF with Survivable Super High Frequency (SSHF) for uninterrupted, jam-resistant nuclear C2 fleetwide. FY25 launches replacement of legacy UHF comms with Mobile User Objective System (MUOS) secure, jam-resistant BLOS. E-4B airframes are viable to approximately 2033, but phaseout of commercial 747-200s hampers continued sustainment.
USAF awarded Sierra Nevada Corp. the $13 billion Survivable Airborne Operations Center (SAOC) contract to replace the fleet on April 26, 2024. The company bought five new-generation 747-8 Intercontinental airframes from Korean Airlines, the first of which arrived in Dayton, Ohio, to begin conversion in June 2024. The replacement fleet will be designated E-4C and is scheduled for delivery through 2036.
E-4 NAOC Technical Data
Contractors: Boeing; Raytheon (FAB-T); L3Harris (SSHF).
First Flight: June 13, 1973 (E-4A); June 10, 1978 (E-4B).
Delivered: December 1974-1985.
IOC: December 1974 (E-4A); January 1980 (E-4B).
Production: Four.
Inventory: Four.
Operator: AFGSC.
Aircraft Location: Offutt AFB, Neb.
Active Variant: •E-4B. Modified Boeing 747-200 equipped as a NAOC.
Dimensions: Span 195.7 ft, length 231.3 ft, height 63.4 ft.
Weight: Max T-O 800,000 lb.
Power Plant: Four General Electric CF6-50E2 turbofans, each 52,500 lb thrust.
Performance: Speed 602 mph, range 7,130 miles, 12-hr normal endurance, 72-hr with air refueling.
Ceiling: Above 30,000 ft.
Accommodation: Two pilots, navigator, flight engineer, up to 110 battle staff/mission crew.
