The E-4 series are specially modified from the Boeing 747-200B for the National Emergency Airborne Command Post (NEACP) program.

An E-4 when in action is denoted a "National Airborne Operations Center" (NAOC) and has been nicknamed the "Doomsday plane".

When the airline did not complete the order, Boeing offered the airframes to the United States Air Force, as part of a package leading to a replacement for the older EC-135J National Emergency Airborne Command Post (NEACP).

[citation needed] The third E-4A was powered by the GE F103 engine, which was later made standard and retrofitted to the previous two aircraft.

The A-model effectively housed the same equipment as the EC-135, but offered more space and an ability to remain aloft longer than an EC-135.

[5] In November 1973, it was reported that the program cost was estimated to total $548 million, equivalent to $3.76 billion in 2023 for seven 747s, with six as operational command posts and one more for research and development.

On 21 December 1979, Boeing delivered the first E-4B, AF Serial Number 75-0125,[5] which was distinguished from the earlier version by the presence of a large streamlined radome on the dorsal surface directly behind the upper deck.

With in-flight aerial refueling it is capable of remaining airborne for a considerable period, limited only by consumption of the engines' lubricants.

The consoles are configured to provide access to or from the automated data processing, automatic switchboard, direct access telephone and radio circuits, direct ("hot") lines, monitor panel for switchboard lines, staff, and operator inter-phone and audio recorder.

Typically three of the six crew positions were occupied here by specialized US Air Force technicians that were responsible for the proper monitoring and distribution of all communications power, cooling, and reliability.

2 (Tech 2, TC2) was responsible for maintaining all UHF communications between the aircraft and the Nightwatch GEP (Ground Entry Points).

[citation needed] The E-4 fleet was originally deployed in 1974,[1] when it was termed National Emergency Airborne Command Post (NEACP), often pronounced "kneecap".

The aircraft was to provide a survivable platform to conduct war operations in the event of a nuclear attack.

[14] The aircraft were originally stationed at Andrews Air Force Base, Maryland, so that the U.S. president and secretary of defense could access them quickly in the event of an emergency.

The name "Nightwatch" originates from the richly detailed Rembrandt painting, The Night Watch, that depicts local townsfolk protecting a town.

[1] The 24-hour alert status at Andrews AFB ended when President Clinton ordered the aircraft to remain at Offutt unless needed.

On 11 September 2001, an aircraft closely resembling an E-4B was spotted and filmed orbiting the Washington, D.C. area by news outlets and civilians, after the attack on the Pentagon.

[19] Air traffic control recordings and radar data indicate this E-4B call sign VENUS77 became airborne just before 9:44 am, circled north of the White House during its climb, and then tracked to the south of Washington, D.C., where it entered a holding pattern.

[23] In January 2006, Secretary of Defense Donald Rumsfeld announced a plan to retire the entire E-4B fleet starting in 2009.

[33][34] This aircraft is to be developed by Sierra Nevada Corporation collaborating with Rolls Royce, based on the Boeing 747-8I.

[35][36][37][38] Data from USAF Fact Sheet,[1] Boeing 747-200 specifications[42]General characteristics Performance 12 hours (without refueling) The E-4B plays a prominent role in two motion pictures.

In the 1990 HBO film By Dawn's Early Light, following a nuclear strike by the Soviets, the aircraft serves as a flying platform for the presumed president, the ex–Secretary of the Interior, who is played by Darren McGavin.

In the 2002 motion picture The Sum of All Fears, the president and his staff travel on an E-4B, following the detonation of a nuclear weapon by terrorists.

National Geographic produced a television special on doomsday planning of the U.S., which includes footage from inside an E-4B during a drill.