Boeing E-4

Boeing E-4
Boeing E-4
White jet with blue cheatline in-flight over land, flying left. The aircraft features a distinctive bump above the usual 747's trademark nose profile
E-4B in flight
Role Airborne command post
Manufacturer Boeing
Introduction 1974
Retired June 20, 2015 (planned)
Status In service
Primary user United States Air Force
Number built 4
Unit cost US$223 million (1998 dollars)[1]
Developed from Boeing 747-200

The Boeing E-4 Advanced Airborne Command Post, with a project name of "Nightwatch",[2] is an aircraft operated by the United States Air Force (USAF). To create the E-4 series, four Boeing 747-200 airframes were specially modified to serve 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 55th Wing located at Offutt Air Force Base, near Omaha, Nebraska.



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 USAF as part of a package leading to a replacement for the older EC-135J NEACP (National Emergency Airborne Command Post). 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. The first E-4A was completed at the Boeing plant outside Seattle, Washington in 1973. E-Systems won the contract to install interim equipment in these three aircraft, and the first completed E-4A was delivered to Andrews AFB, Maryland in December 1974. The next two were delivered in 1975, the third differed by being 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.[3]

Additionally the E-4 was capable of operating the "Looking Glass" mission of the Strategic Air Command (SAC).

In December 1973 a fourth aircraft was contracted for, which 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),[3] which was distinguished from the earlier version by the presence of a large "hump" on the dorsal surface directly behind the upper deck. This contains the aircraft's SHF satellite antenna.[4] By January 1985 all three E-4As had been retrofitted to E-4B models.[3] The E-4B offered a vast increase in communications capability over the previous model and was considered to be 'hardened' against the effects of electromagnetic pulse (EMP) from a nuclear blast. Hardening the aircraft meant that all equipment and wiring on board was shielded from EMP. Additional steps were taken to block radiation from the aircraft's cabin air management system and cockpit, including the novel use of the same screens used to cover the windows of microwave ovens placed over the flight deck windows.

Estimates at the time of the production of the first E-4B placed the developmental cost at nearly US$ 1 billion.[citation needed] The roll out cost of the fleet was placed at approximately US$ 250 million each. In 2005 the Air Force awarded Boeing a US$2 billion contract for the continued upgrade of the E-4B fleet.[citation needed] This contracted work is expected to take five years to complete.


A right front view of an E-4 advanced airborne command post (AABNCP) (AF Serial No. 75-0125) on the electromagnetic pulse (EMP) simulator for testing.

The E-4B is designed to survive an EMP with systems intact,[5] and has state-of-the-art direct fire countermeasures. The E-4B uses analog instruments because they are less susceptible to an EMP.[6] The E-4B is capable of operating with a crew of 48 to 112 people, the largest crew of any aircraft in US Air Force history. With in-flight 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 takes two fully loaded KC-135 tankers to fully refuel an E-4B.

The E-4B has three operational decks; upper, middle and lower.

Upper deck

The flight deck

The flight deck contains the pilot's, copilot's, navigator's and flight engineer's stations, including a special navigation station not normally found on commercial Boeing 747s. A lounge area and sleeping quarters for flight crews and other personnel are located aft of the flight deck. The flight crew consists of an aircraft commander, co-pilot, navigator and flight engineer.

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 has the capability of projecting computer graphics, overhead transparencies or 35 mm slides to either the conference room or the briefing room either singularly or simultaneously.

The battle staff comprises force status controllers (3), emergency action controllers, operations controller, communications controller, intelligence planners (4), operations planners (4), logistic planners (4), chief of battle staff, airborne launch system officers (2), weather officer, reconnaissance planner, damage assessment officer and administrators (2), a total of 26; and communications operators (5), radio maintenance men (5) and switchboard operators (2), a total of 15. The Looking Glass missions were commanded by a general officer with two staff officers, while 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.

Operations team area

Behind the projection 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.

Technical Control area

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 3 of the 6 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 #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 #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 also 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.

Rest area

The rest area, which occupies the remaining portion of the aft main deck, provides a rest and sleeping area for the crew members.

Forward entry area

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. Additionally, four seats are located on the left side of the forward entry area for the security guards and the stewards.

NCA area

Behind the forward entry area is the NCA area, which is designed and furnished as an executive suite. It contains an office, a lounge and sleeping area, and a dressing room. Telephone instruments in this area provide the NCA with secure and clear worldwide communications.

Briefing room

The briefing room contains a briefing table with three executive seats, eighteen additional seats, a lectern and two rear projection screens.

Communications control area

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. The E-4B can communicate with the ground over a wide range of frequencies covering virtually the entire radio communications spectrum from 14 kHz to 8.4 GHz. Ground stations can link the E-4B into the main US ground-based communications network.

Flight avionics area

The flight avionics area contains the aircraft systems power panels, flight avionics equipment, liquid oxygen converters and storage for baggage and spare parts.

Lower Lobe

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. AC/DC powered hydraulic retractable On-Board Folding Airstair by Airweld, Inc. is located in the forward right side of the forward lower equipment area, are 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 5 mile long 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 ballistic missile submarines, is also particularly effective in picking up EMP.

Operational history

The E-4 fleet was originally deployed in 1974,[1] when it was termed National Emergency Airborne Command Post or 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 operations of the E-4, the media dubbed the aircraft as "the doomsday planes".

The aircraft were originally stationed at Andrews Air Force Base in Maryland, so that the U.S. President and Secretary of Defense could access them quickly in the event of an emergency. The origin of the name "Nightwatch" comes from the richly detailed Rembrandt painting of the same name depicting local townsfolk protecting a town and 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.

When a President boards the E-4, its call sign becomes "Air Force One". (NEACP aircraft originally used the static callsign "Silver Dollar"; this callsign faded from use when daily callsigns were put in use.) The E-4B also serves as the Secretary of Defense's preferred means of transportation when traveling outside the United States.[7] 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.

All E-4s were converted to B-models by 1985.[1] With the adoption of two highly-modified Boeing 747-200Bs (known as VC-25A in Air Force parlance) 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 crews to natural disaster sites and serving as a temporary command post on the ground until facilities could be built on site. Evidently 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.[8]

The "cocked" or "on alert" E-4B is manned 24 hours a day with a watch crew on board guarding all communications systems awaiting a launch order (klaxon launch). Those crew members not on watch would be in the alert barracks, gymnasium, or at other base facilities. The 24 hour alert status at Andrews AFB ended when President Clinton ordered the aircraft to remain at Offutt unless needed, though relief crews remain based at Andrews and Wright-Patterson Air Force Base. One E-4B is kept on alert at all times.[1]

In January 2006, Secretary of Defense Donald Rumsfeld announced the entire E-4B fleet would be retired starting in 2009. His replacement Robert Gates reversed this decision in May 2007. The E-4B fleet will remain in service until at least 2015.[9] This is due in no small part to the unique capabilities of the E-4B, which cannot be duplicated by any other single aircraft in Air Force service, as well as the recent resurrection of Russian Military forces under president Vladimir Putin, and also the cancellation in 2007 of the E-10 MC2A program, which was considered a successor aircraft to the EC-135 and E-8, and could also perform many of the same tasks of the E-4B. In addition, despite its build cost, the E-4B is comparatively inexpensive to maintain and operate, as it uses the engines and structural components of the civilian 747, which have become plentiful following the demise of several airlines in the early 21st century.

All four produced are currently operated by the United States Air Force, and are assigned to the 1st Airborne Command Control Squadron (1ACCS) of the 55th Wing at Offutt Air Force Base, Nebraska. Maintenance and crews are provided by Air Combat Command.[1] Operations are coordinated by United States Strategic Command.[1]

E-4B and two C-32s at Defence Establishment Fairbairn, Canberra, Australia during bilateral defense talks, February 2008.

September 11, 2001

On 11 September 2001, an aircraft closely resembling an E-4B was spotted orbiting the Washington D.C. area by news outlets and citizens, during the attack on the Pentagon. This aircraft sighting has added fuel to the continued speculation and debate concerning the September 11 attacks.[10][11] In his book Black Ice, author Dan Verton identifies this aircraft as an E-4B taking part in the 2001 operational exercise "Global Guardian". The exercise was canceled when the first plane struck the World Trade Center, and the E-4B, operating under call sign "Venus 77", which was waiting on the ramp at Andrews AFB, requested emergency clearance and immediately took off. The aircraft initially requested clearance for a direct route to Wright-Patterson AFB, in Dayton, Ohio, and was in the process of receiving clearance while it was seen circling the capital at low altitude during the attack on the Pentagon. Four minutes later the aircraft requested clearance to circle sixty miles south of Washington D.C. Eight minutes after takeoff the aircraft requested clearance to circle Richmond, Virginia at an altitude of 19,000, where it remained for the duration of the attack.[12]


Three produced; later converted to E-4Bs. No bulge (housing equipment) on top of fuselage.
Powered by 52,500-lb CF6-50E2 engines. Has electromagnetic pulse protection, nuclear and thermal effects shielding, advanced electronics, and a wide variety of communications equipment.

Specifications (E-4B)

Data from USAF Fact Sheet,[1] Boeing 747-200 specifications[13]

General characteristics


Notable appearances in media

The E-4B plays a prominent role in two motion pictures. In the HBO film By Dawn's Early Light, following a nuclear strike by the Russians the aircraft serves as a flying platform for the presumed president, played by Darren McGavin. The aircraft is pursued by a Boeing EC-135 "Looking Glass", which is attempting to intercept it. In the 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. In the novel, the Vice-president and his family are aboard Kneecap after terrorists explode a nuclear bomb in Denver while the President and his National Security Advisor are stuck at Camp David during a blinding snowstorm.

National Geographic produced a television special on doomsday planning of the United States which includes footage from inside an E-4 during a drill.[6]

See also

Related development
Aircraft of comparable role, configuration and era

Related lists
  • List of active military aircraft of the United States


  1. ^ a b c d e f g E-4B fact sheet, USAF, October 2007, retrieved 8 May 2007.
  2. ^ FAA Order 7610.4K, Special Military Operations, Chapter 12, §1. FAA
  3. ^ a b c Michell 1994, p.265.
  4. ^ Bowers 1989, p.528.
  5. ^ Dendy IV, Staff Sgt. John B. "Around the clock with the E-4B". USAF Airman magazine, May 2000.
  6. ^ a b "American Doomsday" overview, video clip. National Geographic.
  7. ^ Gilmore, Gerry J. "Rumsfeld Uses 'Flying Pentagon' To Communicate During Trips", US Department of Defense, 1 August 2005.
  8. ^ see "National Airborne Operations Center", Oct. 23rd, 2004 at
  9. ^ Francillon 2008, p.37.
  10. ^ 9/11: The mystery plane. CNN, 12 September 2007.
  11. ^ Mystery 9/11 aircraft. The Raw Story, 13 September 2007.
  12. ^ e-4b plane - Google Search
  13. ^ Boeing 747-200 Technical Specifications, Boeing
  • Bowers, Peter M. Boeing Aircraft since 1916. London:Putnam, 1989. ISBN 0-85177-804-6.
  • Eden, Paul, ed. The Encyclopedia of Modern Military Aircraft. London, UK: Amber Books, 2004. ISBN 1-904687-84-9. 
  • Francillon, René J. "Doomsday 747s: The National Airborne Operations Center". Air International, December 2008. Key Publishing, Syamford, Lincs, UK. pp. 32–37.
  • Gunston, Bill. Spy Planes and Electronic Warfare Aircraft ISBN 0-668-05825-0.
  • Jenkins, Dennis R. Boeing 747-100/200/300/SP (AirlinerTech Series, Vol. 6). Specialty Press, 2000. ISBN 1580070264.
  • Michell, Simon. Jane's Civil and Military Upgrades 1994-95. Coulsden, Surrey, UK: Jane's Information Group, 1994. ISBN 0-7106-1208-7.
  • Verton, Dan Black Ice: The Invisible Threat of Cyber-Terrorism (2003) ISBN 978-0072227871.

External links

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