E-4B Mission The E-4B serves as the National Airborne Operations Center for the president and secretary of defense. In case of national emergency or destruction of ground command control centers, the aircraft provides a highly survivable, command, control and communications center to direct U.S. forces, execute emergency war orders and coordinate actions by civil authorities. Features Air Combat Command (ACC) is the Air Force single-resource manager for the E-4B, and provides aircrew, maintenance, security and communications support. The U.S. Strategic Command actually controls E-4B operations and provides personnel for the airborne operations center. The E-4B, a militarized version of the Boeing 747-200, is a four-engine, swept-wing, long-range, high-altitude airplane capable of being refueled in flight. Its larger size provides approximately triple the floor space of the earlier EC-135 command post. The main deck is divided into six functional areas: a command work area, conference room, briefing room, an operations team work area, and communications and rest areas. An E-4B crew may include up to 114 people, including a joint-service operations team, an ACC flight crew, a maintenance and security component, a communications team and selected augmentees. The E-4B has electromagnetic pulse protection, an electrical system designed to support advanced electronics and a wide variety of new communications equipment. Other improvements include nuclear and thermal effects shielding, acoustic control, an improved technical control facility and an upgraded air-conditioning system for cooling electrical components. An advanced satellite communications system improves worldwide communications among strategic and tactical satellite systems and the airborne operations center. To provide direct support to the president and the secretary of defense, at least one E-4B is always on alert at one of many selected bases throughout the world. Background The E-4B evolved from the E-4A, which had been in service since late 1974. The first B model was delivered to the Air Force in January 1980, and by 1985 all aircraft were converted to B models. All E-4B are assigned to the 55th Wing, Offutt Air Force Base, Neb. General Characteristics Primary Function: Airborne operations center Builder: Boeing Aerospace Co. Power Plant: Four General Electric CF6-50E2 turbofan engines Thrust: 52,500 pounds each engine Length: 231 feet, 4 inches (70.5 meters) Wingspan: 195 feet, 8 inches (59.7 meters) Height: 63 feet, 5 inches (19.3 meters) Maximum Takeoff Weight: 800,000 pounds (360,000 kilograms) Endurance: 12 hours (unrefueled) Ceiling: Above 30,000 feet (9,091 meters) Unit Cost: $223.2 million (fiscal 98 constant dollars) Crew: Up to 114 Date Deployed: January 1980 Inventory: Active force, 4; ANG, 0; Reserve, 0 October 2005