The Boeing E-4 Advanced Airborne Command Post (AACP), the current "Nightwatch" aircraft,. is a series of strategic command and control military aircraft operated by the United States Air Force (USAF). The E-4 series are specially modified from the Boeing 747-200B for the National Emergency Airborne Command Post (NEACP) program. One of its primary purposes is continuity of government during nuclear warfare, thus being nicknamed the "Doomsday plane".
The E-4 serves as a survivable mobile command post for the National Command Authority, namely the president of the United States, the secretary of defense, and successors. The four E-4s are operated by the 1st Airborne Command and Control Squadron of the 595th Command and Control Group located at Offutt Air Force Base, near Omaha, Nebraska. An E-4 when in action is denoted a "National Airborne Operations Center" (NAOC).
The E-4B aircraft are to be replaced by the SNC E-4C Survivable Airborne Operations Center.
Development Two of the original 747-200 airframes were originally planned to be commercial airliners. 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). Under the 481B NEACP program the Air Force Electronic Systems Division awarded Boeing a contract in February 1973 for two unequipped aircraft, designated E-4A, powered by four P&W JT9D engines, to which a third aircraft was added in July 1973.
In 1973, the first E-4A was completed at the Boeing plant in Everett, Washington. E-Systems won the contract to install interim equipment in these three aircraft. In July 1973, the first completed E-4A was delivered to Andrews Air Force Base, Maryland. The next two were delivered in October 1973 and October 1974. 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.Michell 1994, p. 265.
In December 1973, a fourth aircraft was ordered. It was fitted with more advanced equipment, resulting in the designation E-4B. On 21 December 1979, Boeing delivered the first E-4B, AF Serial Number 75-0125, which was distinguished from the earlier version by the presence of a large streamlined radome on the dorsal surface directly behind the upper deck. This contains the aircraft's SHF satellite antenna.Bowers 1989, p. 528.
In November 1973, it was reported that the program cost was estimated to total $548 million, equivalent to $ billion in for a planned seven 747s, with six as operational command posts and one more for research and development. The final 3 aircraft were not built.
By January 1985, all three E-4As had been retrofitted to E-4B models. The E-4B offered a vast increase in communications capability over the previous model and was considered to be 'hardened' against the effects of a nuclear electromagnetic pulse (EMP) from a nuclear explosion. Hardening the aircraft meant that all equipment and wiring on board was shielded from an EMP.
In 2005, the Air Force awarded Boeing a five-year, US$2 billion contract, equivalent to $ billion in , for the continued upgrade of the E-4B fleet. In addition to the purchase and upgrade costs, the E-4 costs nearly $160,000 per hour, , for the Air Force to operate. The E-4B fleet had an estimated unit cost of approximately US$223.2 million each in 2024.
Design
The E-4B is designed to survive an EMP with systems intact,. and has state-of-the-art direct fire countermeasures. Many older aircraft have been upgraded with glass cockpits. The E-4B still uses traditional analog flight instruments, as they are less susceptible to damage from an EMP blast."American Doomsday" overview , video clip . National Geographic.
The E-4B is capable of operating with a crew up to 112 people, including flight and mission personnel, the largest crew of any aircraft in US Air Force history. With in-flight aerial refueling it is capable of remaining airborne for a considerable period, limited only by consumption of the engines' lubricants. In a test flight for endurance, the aircraft remained airborne and fully operational for 35.4 hours. It is designed to be able to remain airborne for a full week in the event of an emergency. It takes two fully loaded KC-135 tankers to fully refuel an E-4B. The E-4B has three operational decks: upper, middle, and lower.
Middle deck The middle deck contains the conference room, which provides a secure area for conferences and briefings. It contains a conference table for nine people. Aft of the conference room is a projection room serving the conference room and the briefing room. The projection room had the capability of projecting computer graphics, overhead transparencies, or 35 mm slides to the conference room and/or the briefing room, and has since been modernized with flat screen displays.
The battle staff includes various controllers, planners, launch system officers, communications operators, a weather officer, administrative and support personnel, and a chief of battle staff. The Operation Looking Glass missions were commanded by a general officer with two staff officers. The National Airborne Operations Center (NAOC) may rendezvous and embark a member of the National Command Authority (NCA) from an undisclosed location. There are at least 48 crew aboard any E-4B mission.
Behind the briefing room is the operations team area, containing the automatic data processing equipment and seats and console work areas for 29 staff members. 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.
The aft compartment at the end of the main deck is the Technical Control (Tech Control) area. This area was the nerve center for all communications and communications technicians. 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.
The Technical Controller No. 1 (Tech 1, TC1) was the direct interface with the aircraft Flight Engineer and Flight Crew. This position was also the main focal point for all communications related issues. The Technical Controller No. 2 (Tech 2, TC2) was responsible for maintaining all UHF communications between the aircraft and the Nightwatch GEP (Ground Entry Points). These GEP's provided 12 voice lines to the aircraft which were used in the day-to-day operations of the mission. Secure Voice was provided. The SHF Operator (or technician) maintained the SHF satellite link and provided other worldwide communications services, probably having replaced a lot of the UHF capabilities.
The rest area, which occupies the remaining portion of the aft main deck, provides a rest and sleeping area for the crew members. The rest area contains storage for food and is used for religious ceremonies.
Within the forward entry area is the main galley unit and stairways to the flight deck and to the forward lower equipment area. This area contains refrigerators, freezers, two convection ovens, and a microwave oven to give stewards the capability to provide more than 100 hot meals during prolonged missions. Four seats are located on the left side of the forward entry area for the secret service and the stewards.
Behind the forward entry area, is the National Command Authority (NCA) area, which is designed and furnished as an executive suite. It contains an office, a lounge, a sleeping area, and a dressing room. Telephone instruments in this area provide the NCA with secure and clear worldwide communications.
The briefing room contains a briefing table with three executive seats, 18 additional seats, a lectern, and two 80-inch flat screen LED monitors flush mounted to the partition.
The communications control area is divided into a voice area and a data area. The voice area, located on the right side of the compartment, contains the radio operator's console, the semi-automatic switchboard console, and the communication officer's console. The data area, located on the left side of the area, contains the record communications console, record data supervisor's console, high speed DATA/AUTODIN/AFSAT console, and LF/VLF control heads.
Lower deck The forward lower equipment room contains the aircraft's water supply tanks, 1200 kVA electrical power panels, step-down transformers, VLF transmitter, and SHF SATCOM equipment. An AC/DC powered hydraulic retractable airstair is located in the forward right side of the forward lower equipment area, installed for airplane entry and exit. In the event of an emergency, the airstair can be jettisoned. The aft lower lobe contains the maintenance console and mission specific equipment.
The lower trailing wire antenna (TWA) area contains the aircraft's TWA reel—which is used by up to 13 communications links—the antenna operator's station, as well as the antenna reel controls and indicators. Much attention has been given to hardening this area against EMP, especially as the TWA, essential for communicating with Ohio-class ballistic missile submarines, is particularly effective in picking up EMP.
The flight avionics area contains the aircraft systems power panels, flight avionics equipment, liquid oxygen converters, and storage for baggage and spare parts.
Operational history
The E-4 fleet was originally deployed in 1974, 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. Early in the E-4's service, the media dubbed the aircraft as "the doomsday planes". The E-4 was also capable of operating the "Looking Glass" missions of the Strategic Air Command (SAC).Alwin 1999, p. 608.
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. It was selected by the Squadron's first commanding officer. Later, the aircraft were moved to Offutt Air Force Base where they would be safer from attack. Until 1994, one E-4B was stationed at Andrews Air Force Base at all times so the president could easily board it in times of world crisis.
The NEACP aircraft originally used the static call sign "Silver Dollar". This call sign faded from use when daily call signs were put in use. The E-4B serves as the secretary of defense's preferred means of transportation when traveling outside the U.S.Gilmore, Gerry J. "Rumsfeld Uses 'Flying Pentagon' To Communicate During Trips" . US Department of Defense, 1 August 2005. The spacious interior and sophisticated communications capability provided by the aircraft allow the Secretary's senior staff to work for the duration of the mission.
With the adoption of two highly modified Boeing 747-200Bs, Air Force designation VC-25A, to serve as Air Force One in 1989, and the end of the Cold War, the need for NEACP diminished. In 1994, NEACP began to be known as NAOC, and it took on a new responsibility: ferrying Federal Emergency Management Agency (FEMA) crews to natural disaster sites and serving as a temporary command post on the ground, until facilities could be built on site. No E-4B was employed during the Hurricane Katrina disaster of 2005, though one E-4B was used by FEMA following Hurricane Opal in 1995.