The US Air Force operates four E-4 B Nightwatch aircraft [or AACP for Advanced Airborne Command Post] from Offutt Air Force Base in Nebraska to enable the American executive branch to coordinate a potential response in the event of a nuclear attack against the United States. These aircraft are assigned to the 595th Command and Control Group.
The E-4 B, a unique variant of the Boeing B747-22, is renowned for its ability to withstand nuclear radiation and electromagnetic pulses. This ‘Doomsday Plane’ is refuelable in-flight and is equipped with a range of robust communication systems. These include a VLF (very low frequency) device for contacting submerged nuclear ballistic missile submarines (SSBNs) and a satellite communication system that enables global communication for civilian and military officials.
At least one of these four E-4Bs is on alert 24/7. The US Federal Emergency Management Agency can also request them in natural disasters.
In 2020, the US Air Force revealed its intention to replace its E-4Bs by the 2030s as part of the Survivable Airborne Operations Center (SAOC) program. Boeing was initially favored due to its experience in this type of capability. However, due to the inability to reach an agreement with the Pentagon regarding a fixed-price contract and likely because of delays and cost escalation of the two future presidential aircraft, ‘Air Force One,’ the company was excluded.
Finally, on April 26, the US Air Force announced it would award the SAOC contract to Sierra Nevada Corp. This program’s potential cost could reach $13 billion. An initial allocation of $59 million will be released to fund preliminary research and development work.
“The development of this essential weapon system for national security ensures that the Department of Defense’s nuclear command, control, and communication capabilities will be operationally relevant and secure for decades to come,” said a spokesperson for the US Air Force.
In detail, the successor to the E-4B will also be a modified and “strengthened” commercial aircraft to meet military requirements. No specific model has been specified at this time. According to Aviation Week, the US Air Force intends to acquire between eight and ten units.
E-4 Doomsday Plane
In the 1970s, the National Airborne Operations Center (NAOC) was established. In anticipation of the potential outbreak of a Third World War, the E-4B was designed to transport the National Command Authority (NCA), which consisted of the President of the United States and other high-ranking officials. The strategy involved overseeing state and armed forces operations from an underground facility in Virginia and the E-4B. This historical context highlights the E-4 B’s enduring legacy and its role in shaping US national security.
When selecting the platform for the US Air Force’s command post, factors such as speed, efficiency, and comfort were considered, but priority was given to the size of the aircraft and its long-flight endurance. The Pentagon wanted the E-4 to remain airborne during the exchange of the first nuclear strikes when communication was particularly difficult, and many airfields could already be destroyed. The wide-body Boeing 747, with its vast internal volumes and long flight endurance, was well-suited for the command post. The 747 could accommodate numerous specialized equipment, provide protection against electromagnetic pulses, and create a comfortable environment for VIP passengers.
The E-4 made its first flight on June 13, 1973. Three aircraft delivered in 1974 were designated as E-4A and equipped similarly to their predecessors – the EC-135J. The fourth aircraft, the E-4B, delivered to the customer in December 1974, carried new equipment. Over time, all E-4s were upgraded to E-4Bs.
On board the E-4B, the President of the United States could perform the functions of the Commander-in-Chief of the Armed Forces. The main cabin, with an area of 511 square meters, was allocated for the President and his staff to work. The cabin is divided into five sections: for the crew, the NCA (equivalent to the White House Situation Room), a conference room for the Armed Forces staff, and communication, reconnaissance, and management. The rest of the areas are located on the second deck.
The E-4B is equipped with systems to protect against the effects of nuclear explosions. The aircraft is fitted with low—and ultra-low-frequency communication systems and satellite communication equipment. Hence, the President’s address can be broadcast over radio networks and even ordinary telephone lines.
The E-4B differs from the E-4A in that it has additional low-frequency and ultra-high-frequency radio equipment, the antennas of which are located in the fuselage fairings. All aircraft components, including engines, avionics, and wiring, have an extended service life.
During normal flight, the aircraft’s speed is 933 km/h, and with refueling, the E-4B can remain airborne for 72 hours. However, in the event of war, the aircraft can fly without landing and with refueling for up to a week. The E-4B, like the presidential VC-25A (also based on the 747), has its flight endurance limited only by the capacity of the engine oil tanks. The powerplant consists of four General Electric F103-PW-100 (CF6-50-E2) turbofan engines with a thrust of 233.53 kN each.
The E-4B was initially designated AABNCP (Advanced Airborne National Command Post) and later changed to NEACP (National Emergency Airborne Command Post). The modern term NAOC partially reflects the changed situation in the world.
There were plans to upgrade the E-4B with more advanced targeting equipment and improvements to the onboard defense system.